RE: RE: RE: Stand-by (Oracle9i Data Guard) vs. Replication
Robert, If I understand your requirements correctly, You have multiple sites separated geographically ( 200 Miles perhaps..?? ) and you are looking for a highly available , 'Multimaster' kinda environment. This kind of setup is common in oh-don't-say-the-name-companies i.e. 'dot bombs' and companies with regional offices around the world, with certain variations. I think off the top of the top of head I can say Amazon as an example. To clear some points before jumping to solutions, 1. Is the critical data would be updated in the sites..? 2. If yes , are you expecting the other sites to 'see' this update...? 3. If one site is down, then are you expecting the other sites to share the load or you have the closest site in take in all the load...? Depending upon the answer you have to make a choice. For example, I notice you have been discussing RAC as a possible solution. In this case ,since you have multiple sites , which is going to be the Primary..? or are you proposing to use a RAC for each site..? Wouldn't a third party assisted solution be more scalable and cost effective..? Like EMC or HP's XP storage solution has some kinda 'track' or 'Block' replicating mechanism between the storage, which is extendable in term of geographical location ? Or if you are looking to share the load like in question 3 above, then wouldnt it be easy to Get a replicating software to help replicate the data in real time or near real time ? Example , like said before quest softwares shareplex. This can give you master-master replication capabilities. Just my 2 cents. Cheers, RS --- Freeman, Robert [EMAIL PROTECTED] wrote: Log application services can run in foreground or background now, but I don't think the database can be open read-only at the same time while doing managed recovery, even in 9i. __ Do You Yahoo!? Yahoo! Movies - coverage of the 74th Academy Awards® http://movies.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Sakthi , Raj INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: RE: RE: Stand-by (Oracle9i Data Guard) vs. Replication
1. Is the critical data would be updated in the sites..? Yes... 2. If yes , are you expecting the other sites to 'see' this update...? Yes... 3. If one site is down, then are you expecting the other sites to share the load or you have the closest site in take in all the load...? Yes but add this requirement as a wrinkle, the sites have to be able to run independently of each other (e.g. a WAN failure) and then resync with each other after a period of time. Finally, this is a bit different than Amazon in that this system has some human safety considerations associated with it. Amazon outage might represent lost sales, outage of this system could represent lost lives. Needless to say, I'm being very careful about the architecture we use. I've implemented replication solutions before as well as stand-by database solutions. But the replication solutions to this point have been very simple and not nearly as complex... so I was hoping for someone to say, we do that and here are the issues we ran into. As for RAC, we will be running RAC at each site, and replicating between the RAC cluster. Sites are way to distant for RAC between them through a SAN or some such thing. RF What does shareplex buy me that Oracle's advanced replication does not? Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Tuesday, March 26, 2002 12:38 PM To: Multiple recipients of list ORACLE-L Robert, If I understand your requirements correctly, You have multiple sites separated geographically ( 200 Miles perhaps..?? ) and you are looking for a highly available , 'Multimaster' kinda environment. This kind of setup is common in oh-don't-say-the-name-companies i.e. 'dot bombs' and companies with regional offices around the world, with certain variations. I think off the top of the top of head I can say Amazon as an example. To clear some points before jumping to solutions, 1. Is the critical data would be updated in the sites..? 2. If yes , are you expecting the other sites to 'see' this update...? 3. If one site is down, then are you expecting the other sites to share the load or you have the closest site in take in all the load...? Depending upon the answer you have to make a choice. For example, I notice you have been discussing RAC as a possible solution. In this case ,since you have multiple sites , which is going to be the Primary..? or are you proposing to use a RAC for each site..? Wouldn't a third party assisted solution be more scalable and cost effective..? Like EMC or HP's XP storage solution has some kinda 'track' or 'Block' replicating mechanism between the storage, which is extendable in term of geographical location...? Or if you are looking to share the load like in question 3 above, then wouldn't it be easy to Get a 'replicating' software to help replicate the data in real time or near real time...? Example , like said before quest software's shareplex. This can give you master-master replication capabilities. Just my 2 cents. Cheers, RS --- Freeman, Robert [EMAIL PROTECTED] wrote: Log application services can run in foreground or background now, but I don't think the database can be open read-only at the same time while doing managed recovery, even in 9i. __ Do You Yahoo!? Yahoo! Movies - coverage of the 74th Academy Awards® http://movies.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Sakthi , Raj INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: RE: RE: Stand-by (Oracle9i Data Guard) vs. Replication
Well, being in health care industry myself I know too well what do you mean. Apart from 100s of tousands of $ lost every hour we are down, we have to take some safety also into account. As to the question of advanced replication, having implemented multi-master replication myself I know what a nightmare it could turn out to be . Moreover it wasn't greate shakes in performance either. Only advantage you are looking at when considering a third party software. It is script driven so no info gets stored in data dictionary. How this could be a merit ?...well you don't get hung up on distributed transaction ( 2 phase commit ) problem solving - performance hit which is inevitable. More over I have seen the technology of reading redo logs/archive logs and it seems to be stable and fast. Finally I think it is matter of personal preference also. But I coul dbe wrong. Cheers, RS --- Freeman, Robert [EMAIL PROTECTED] wrote: 1. Is the critical data would be updated in the sites..? Yes... 2. If yes , are you expecting the other sites to 'see' this update...? Yes... 3. If one site is down, then are you expecting the other sites to share the load or you have the closest site in take in all the load...? Yes __ Do You Yahoo!? Yahoo! Movies - coverage of the 74th Academy Awards® http://movies.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Sakthi , Raj INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
Stand-by (Oracle9i Data Guard) vs. Replication
Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
Re: Stand-by (Oracle9i Data Guard) vs. Replication
What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). __ Do You Yahoo!? Yahoo! Movies - coverage of the 74th Academy Awards® http://movies.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Joe Raube INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: Stand-by (Oracle9i Data Guard) vs. Replication
Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). __ Do You Yahoo!? Yahoo! Movies - coverage of the 74th Academy Awards® http://movies.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Joe Raube INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
Re: [RE: Stand-by (Oracle9i Data Guard) vs. Replication]
One way to recover Standby machine is to share a drive from the remote machine, and copy (ftp) the log files to the shared drive every time a new log file was created. Yigal Freeman, Robert [EMAIL PROTECTED] wrote: Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). __ Do You Yahoo!? Yahoo! Movies - coverage of the 74th Academy Awards® http://movies.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Joe Raube INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Yigal Ran INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX
Re: [RE: Stand-by (Oracle9i Data Guard) vs. Replication]
One way to recover Standby machine is to share a drive from the remote machine, and copy (ftp) the log files to the shared drive every time a new log file was created. Yigal Freeman, Robert [EMAIL PROTECTED] wrote: Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). __ Do You Yahoo!? Yahoo! Movies - coverage of the 74th Academy Awards® http://movies.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Joe Raube INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Yigal Ran INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX
RE: Stand-by (Oracle9i Data Guard) vs. Replication
Sorry for interrupting... but our SLAs (requirements docs) do not have such loose language... Things like 'ASAP' and 'as little latency as possible' must be specified in absolute numbers (minutes, hours, days etc.) If it is not spelled out, it's a wide open game of mud slinging ;) - Kirti -Original Message- Sent: Monday, March 25, 2002 11:49 AM To: Multiple recipients of list ORACLE-L Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Deshpande, Kirti INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: Stand-by (Oracle9i Data Guard) vs. Replication
(from the mouth of a replication non-quru) I think you answered your own question. If no network and they want to be up, then synchronous replication is not an option. You're only option is asynchronous replication. One answer that I'm sure EMC would luv to sell you is networked raw disks in conjunction with Oracle Parallel Server (OPS/RAC). If cost is not a problem, then EMC has the solution. It's not their company slogan/mission statement, but it should be. In this scenario you may lose a node but you can trade the problems of asynchronous replication conflict detection and resolution (and maintaining multiple databases), for the OPS locks and false ping problems. If given a choice, I'd take the OPS problems. Brian P. MacLean Oracle DBA, OCP8i Freeman, Robert To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED] Robert_Freema cc: [EMAIL PROTECTED] Subject: RE: Stand-by (Oracle9i Data Guard) vs. Replication Sent by: [EMAIL PROTECTED] om 03/25/02 10:48 AM Please respond to ORACLE-L Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author
Re:RE: Stand-by (Oracle9i Data Guard) vs. Replication
Robert, Given what you've said it would appear that your only choice is going to be symetric/advanced replication, multi-master. The conflict resolution rules may be a bear to set up with 5 sites though. Using a standby db would not be very effective since data updates are dependent on the archive log switch points and that does not address the different sites if your reason for failure is a network related one. Snapshots won't work either since they are read only. Dick Goulet Reply Separator Author: Freeman; Robert [EMAIL PROTECTED] Date: 3/25/2002 9:48 AM Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). __ Do You Yahoo!? Yahoo! Movies - coverage of the 74th Academy AwardsR http://movies.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Joe Raube INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list
RE: [RE: Stand-by (Oracle9i Data Guard) vs. Replication]
Unfortunately, there are synchronization issues with the use of the stand-by since one requirement is that EACH of the 4 sites must be able to run autonomously... in other words, if I take all 4 sites out of stand-by mode, they make changes at all 4 sites and then we have to resynch (after the network is back for example) how the heck do I do that. I thought about using separate schemas for local data, and transportable tablespaces, but there is some data that is shared by the entire network, and that is a problem. RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 1:05 PM To: Multiple recipients of list ORACLE-L One way to recover Standby machine is to share a drive from the remote machine, and copy (ftp) the log files to the shared drive every time a new log file was created. Yigal Freeman, Robert [EMAIL PROTECTED] wrote: Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). __ Do You Yahoo!? Yahoo! Movies - coverage of the 74th Academy Awards® http://movies.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Joe Raube INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing
RE: Stand-by (Oracle9i Data Guard) vs. Replication
Yea yea yea well we don't have quite that level of definition at this point, and I have yet to see absolute numbers come my way. Isn't my project, in fact this is an outside vendor and I'm coming in on the tail end of the projects design phase and being asked, do you agree with this design and I'm saying, now's a fine time to ask. I've asked for additional facts and figures, but pointing my little digits sometimes only get's them bitten off by the big machine that is. The requirements as defined thus far to me are: 1. No more than 5 minutes outage. 2. No data loss 3. each site has to be able to act autonomously. three different kinds of data 1. Network wide data (used by all sites) - critical, no data loss 2. Regional data (specific to a region, not used by other sites) - critical, no data loss 3. Easily recoverable non-critical data. Data loss is tolerable. That being said, they want to replicate between the four sites, and they want to use replication conflict resolution rules to deal with outages and resync of the databases. They claim it will work great, I'm thinking, yea right sounds like a bear to manage. I'd much rather do 9i data guard just off the hip, but as you point out, I do not have lots of info as yet, so we shall see what comes down the pike. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 1:23 PM To: Multiple recipients of list ORACLE-L Sorry for interrupting... but our SLAs (requirements docs) do not have such loose language... Things like 'ASAP' and 'as little latency as possible' must be specified in absolute numbers (minutes, hours, days etc.) If it is not spelled out, it's a wide open game of mud slinging ;) - Kirti -Original Message- Sent: Monday, March 25, 2002 11:49 AM To: Multiple recipients of list ORACLE-L Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Deshpande, Kirti INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX
RE: RE: Stand-by (Oracle9i Data Guard) vs. Replication
Thanks for your thoughts Dick! Actually, look into Data Guard in 9i and you will find that you are no longer constrained by archive log switches!! I'm really concerned with the conflict resolution issues with MM Replication. I've done something like this once before, with only 2 sites, but it's been so long that it's a hazy distant memory. As I recall, the conflict resolution was a bear. They are intending on doing the resolution based on a date column and just saying that the latest date winds... they have a method of keeping the date/time on the servers in sync as long as the network is up, but my concern is what happens when it goes down and that date/time sync no longer is working or what happens when the system goes down and they also replace the hardware and the date/time is not sync'd for several days until the network is back. But... then I ask myself how often that will happen too... ;-) Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 2:37 PM To: Freeman, Robert ; Multiple recipients of list ORACLE-L Robert, Given what you've said it would appear that your only choice is going to be symetric/advanced replication, multi-master. The conflict resolution rules may be a bear to set up with 5 sites though. Using a standby db would not be very effective since data updates are dependent on the archive log switch points and that does not address the different sites if your reason for failure is a network related one. Snapshots won't work either since they are read only. Dick Goulet Reply Separator Author: Freeman; Robert [EMAIL PROTECTED] Date: 3/25/2002 9:48 AM Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). __ Do You Yahoo!? Yahoo! Movies - coverage
RE: Stand-by (Oracle9i Data Guard) vs. Replication
RF, Looks like you are looking for something like quest software's shareplex. A cool tool, although, on the expensive side. It has the ability to replicate with least intrusion and perf impact. ( Or thats what they say...:) ) And noI am not working for quest software...! Cheers, RS --- Freeman, Robert [EMAIL PROTECTED] wrote: Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). __ Do You Yahoo!? Yahoo! Movies - coverage of the 74th Academy Awards® http://movies.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Joe Raube INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing
Re:RE: RE: Stand-by (Oracle9i Data Guard) vs. Replication
Robert, Either way, I do believe that you can't have a standby database in both managed recovery and read only access at the same time which could be your biggest problem. The application would have to understand that under normal circumstances it's getting data from database 'X' and during failures from database 'Y'. This kind of thing gets messy as well. Therefore your best bet is for local objects that are replicated from elsewhere since all sites can update all data your rather stuck. And as far as the network going down, yours in a similar comment that our network specialist made some 2 years ago, until a back hoe operator ripped out about 1/4 mile of fiber near our building. Took the local yokels 4 days to get it repaired. So don't say 'never' as it definitely can come back to bite you. Dick Goulet Reply Separator Author: Freeman; Robert [EMAIL PROTECTED] Date: 3/25/2002 2:52 PM Thanks for your thoughts Dick! Actually, look into Data Guard in 9i and you will find that you are no longer constrained by archive log switches!! I'm really concerned with the conflict resolution issues with MM Replication. I've done something like this once before, with only 2 sites, but it's been so long that it's a hazy distant memory. As I recall, the conflict resolution was a bear. They are intending on doing the resolution based on a date column and just saying that the latest date winds... they have a method of keeping the date/time on the servers in sync as long as the network is up, but my concern is what happens when it goes down and that date/time sync no longer is working or what happens when the system goes down and they also replace the hardware and the date/time is not sync'd for several days until the network is back. But... then I ask myself how often that will happen too... ;-) Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 2:37 PM To: Freeman, Robert ; Multiple recipients of list ORACLE-L Robert, Given what you've said it would appear that your only choice is going to be symetric/advanced replication, multi-master. The conflict resolution rules may be a bear to set up with 5 sites though. Using a standby db would not be very effective since data updates are dependent on the archive log switch points and that does not address the different sites if your reason for failure is a network related one. Snapshots won't work either since they are read only. Dick Goulet Reply Separator Author: Freeman; Robert [EMAIL PROTECTED] Date: 3/25/2002 9:48 AM Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF Robert G. Freeman
Re:RE: Stand-by (Oracle9i Data Guard) vs. Replication
Robert, I think it is possible to use RAC where the corporate data is located on a SAN accessible to all and each region has their own storage that they have RAC'd with the rest of the organization. If one region dies each region continues to function. If the corporate office dies each region continues to function. It sounds complicated and requires fast inter-connectivity between each region and the SAN. Sound reasonable? ROR mª¿ªm [EMAIL PROTECTED] 03/25/02 02:38PM Robert, Given what you've said it would appear that your only choice is going to be symetric/advanced replication, multi-master. The conflict resolution rules may be a bear to set up with 5 sites though. Using a standby db would not be very effective since data updates are dependent on the archive log switch points and that does not address the different sites if your reason for failure is a network related one. Snapshots won't work either since they are read only. Dick Goulet Reply Separator Author: Freeman; Robert [EMAIL PROTECTED] Date: 3/25/2002 9:48 AM Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Ron Rogers INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
RE: RE: RE: Stand-by (Oracle9i Data Guard) vs. Replication
Dick - In the Oracle Backup and Recovery Class I took recently, I recall the instructor saying that restriction had been lifted in Oracle9i. I can't find my note on this, so don't take it as gospel, but it might be worth looking into if that would make a difference in the decisions. Dennis Williams DBA Lifetouch, Inc. [EMAIL PROTECTED] -Original Message- Sent: Monday, March 25, 2002 2:04 PM To: Multiple recipients of list ORACLE-L Robert, Either way, I do believe that you can't have a standby database in both managed recovery and read only access at the same time which could be your biggest problem. The application would have to understand that under normal circumstances it's getting data from database 'X' and during failures from database 'Y'. This kind of thing gets messy as well. Therefore your best bet is for local objects that are replicated from elsewhere since all sites can update all data your rather stuck. And as far as the network going down, yours in a similar comment that our network specialist made some 2 years ago, until a back hoe operator ripped out about 1/4 mile of fiber near our building. Took the local yokels 4 days to get it repaired. So don't say 'never' as it definitely can come back to bite you. Dick Goulet Reply Separator Author: Freeman; Robert [EMAIL PROTECTED] Date: 3/25/2002 2:52 PM Thanks for your thoughts Dick! Actually, look into Data Guard in 9i and you will find that you are no longer constrained by archive log switches!! I'm really concerned with the conflict resolution issues with MM Replication. I've done something like this once before, with only 2 sites, but it's been so long that it's a hazy distant memory. As I recall, the conflict resolution was a bear. They are intending on doing the resolution based on a date column and just saying that the latest date winds... they have a method of keeping the date/time on the servers in sync as long as the network is up, but my concern is what happens when it goes down and that date/time sync no longer is working or what happens when the system goes down and they also replace the hardware and the date/time is not sync'd for several days until the network is back. But... then I ask myself how often that will happen too... ;-) Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 2:37 PM To: Freeman, Robert ; Multiple recipients of list ORACLE-L Robert, Given what you've said it would appear that your only choice is going to be symetric/advanced replication, multi-master. The conflict resolution rules may be a bear to set up with 5 sites though. Using a standby db would not be very effective since data updates are dependent on the archive log switch points and that does not address the different sites if your reason for failure is a network related one. Snapshots won't work either since they are read only. Dick Goulet Reply Separator Author: Freeman; Robert [EMAIL PROTECTED] Date: 3/25/2002 9:48 AM Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your
RE: RE: RE: Stand-by (Oracle9i Data Guard) vs. Replication
Log application services can run in foreground or background now, but I don't think the database can be open read-only at the same time while doing managed recovery, even in 9i. Really, there is no read-only requirement in the architecture I'm looking at. RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 3:46 PM To: Multiple recipients of list ORACLE-L Dick - In the Oracle Backup and Recovery Class I took recently, I recall the instructor saying that restriction had been lifted in Oracle9i. I can't find my note on this, so don't take it as gospel, but it might be worth looking into if that would make a difference in the decisions. Dennis Williams DBA Lifetouch, Inc. [EMAIL PROTECTED] -Original Message- Sent: Monday, March 25, 2002 2:04 PM To: Multiple recipients of list ORACLE-L Robert, Either way, I do believe that you can't have a standby database in both managed recovery and read only access at the same time which could be your biggest problem. The application would have to understand that under normal circumstances it's getting data from database 'X' and during failures from database 'Y'. This kind of thing gets messy as well. Therefore your best bet is for local objects that are replicated from elsewhere since all sites can update all data your rather stuck. And as far as the network going down, yours in a similar comment that our network specialist made some 2 years ago, until a back hoe operator ripped out about 1/4 mile of fiber near our building. Took the local yokels 4 days to get it repaired. So don't say 'never' as it definitely can come back to bite you. Dick Goulet Reply Separator Author: Freeman; Robert [EMAIL PROTECTED] Date: 3/25/2002 2:52 PM Thanks for your thoughts Dick! Actually, look into Data Guard in 9i and you will find that you are no longer constrained by archive log switches!! I'm really concerned with the conflict resolution issues with MM Replication. I've done something like this once before, with only 2 sites, but it's been so long that it's a hazy distant memory. As I recall, the conflict resolution was a bear. They are intending on doing the resolution based on a date column and just saying that the latest date winds... they have a method of keeping the date/time on the servers in sync as long as the network is up, but my concern is what happens when it goes down and that date/time sync no longer is working or what happens when the system goes down and they also replace the hardware and the date/time is not sync'd for several days until the network is back. But... then I ask myself how often that will happen too... ;-) Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 2:37 PM To: Freeman, Robert ; Multiple recipients of list ORACLE-L Robert, Given what you've said it would appear that your only choice is going to be symetric/advanced replication, multi-master. The conflict resolution rules may be a bear to set up with 5 sites though. Using a standby db would not be very effective since data updates are dependent on the archive log switch points and that does not address the different sites if your reason for failure is a network related one. Snapshots won't work either since they are read only. Dick Goulet Reply Separator Author: Freeman; Robert [EMAIL PROTECTED] Date: 3/25/2002 9:48 AM Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we
RE: [RE: Stand-by (Oracle9i Data Guard) vs. Replication]
there is a new white paper (Feb 2002) from Oracle HA Center for Expertise that speaks to making databases maximumly highly available. It suggests a combination of RAC and standby (dataguard) with 9i. My thoughts on your requirements are: first -- I agree with Kirti, you need VERY specific language and should have downtime etc quantified in measurable units. ASAP is not measurable, for some systems that might mean two minutes and for others it might mean days. Get NUMBERS second -- can you run these in separate databases with dblinks? I'd isolate the data based on how available and to whom it has to be available. so I'd consider the Oracle solution for the data that must be available to everyone, then separate servers and databases for the others. third -- understand that it doesn't matter how available your servers and databases are if the networks are also not redundant. Finally -- has anyone at all considered and allowed for downtime for maintenance/upgrades? Just a few thoughts off the top of my head. Rachel --- Freeman, Robert [EMAIL PROTECTED] wrote: Unfortunately, there are synchronization issues with the use of the stand-by since one requirement is that EACH of the 4 sites must be able to run autonomously... in other words, if I take all 4 sites out of stand-by mode, they make changes at all 4 sites and then we have to resynch (after the network is back for example) how the heck do I do that. I thought about using separate schemas for local data, and transportable tablespaces, but there is some data that is shared by the entire network, and that is a problem. RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 1:05 PM To: Multiple recipients of list ORACLE-L One way to recover Standby machine is to share a drive from the remote machine, and copy (ftp) the log files to the shared drive every time a new log file was created. Yigal Freeman, Robert [EMAIL PROTECTED] wrote: Pretty stringent. They want as little latency as possible. Changes at a master should be available to all sites ASAP. Now, they could all go to one central site, and thats ok as long as our networking is healthy, but if it goes down, there is a requirement that they be able to work independently (there are 4-5 sites) and then all changes need to be synchronized. Data loss is secondary to availability however. These requirements smack of trouble to me. Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -Original Message- Sent: Monday, March 25, 2002 11:48 AM To: Multiple recipients of list ORACLE-L What type of requirement or SLA do you have in regards to keeping the instances in sync? -Joe --- Freeman, Robert [EMAIL PROTECTED] wrote: Stand-by (Oracle9i Data Guard) vs. Replication Folks, I have a mission critical system we are architectonic right now. There is some argument of the merits of replication vs. using Standby database going on. Current we have 4 sites that we will be replicating data back and forth between. There are 3 kinds of data: 1. Network Critical data (must be available for entire network) 2. Regional Critical data (only used for a given region. site = region). 3. Regional non-critical data (this is data that is easily recovered from other operational data stores). I can load you up with details, but for now this is the general requirement. We want a given site to be able to work independently of the other sites in the event of network failure (WAN). What I'm looking for is your experience with using replication for HA solutions vs. stand-by databases. I've also considered using standby databases as a possible solution to this problem, along with using transportable tablespaces to re-sync the databases once everything comes up. I'm concerned with replication in that there is allot to break, and I'm concerned about synchronization issues in general with either solution. Thoughts? RF Robert G. Freeman - Oracle8i OCP Oracle DBA Technical Lead CSX Midtier Database Administration The Cigarette Smoking Man: Anyone who can appease a man's conscience can take his freedom away from him. -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Freeman, Robert INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet access / Mailing Lists
