RE: Scsi I/O speed
also, consider turning OFF command tag queueingcheck mobo drivers for i/o bus-related hwcheck w/t vice w/b cache, look at stripe stride vice os block size. Ross -Original Message- Sent: Wednesday, July 11, 2001 1:41 PM To: Multiple recipients of list ORACLE-L Kevin Kostyszyn wrote: Hi all, I was measuring the i/o performance of my scsi drives and I have a quick question that maybe someone could shed some light upon. Currently I am using Ultra 2/Wide scsi conrollers, this is supposed to have an I/O of 80mb/s. Well, when I perform the test all of the machines seem to be operation at halp of the max speed. One operates at about 20mb/s read and write and the others are even slower than that. Now on the first one, it is the only HD on the controller, on the others there are two disks. Even on my Ultra/160 it seems to be maxing out at 40 read and write. Am I missing something? Am I reading this the wrong way? Help:( Sincerely, Kevin Kostyszyn DBA Dulcian, Inc www.dulcian.com [EMAIL PROTECTED] Kevin, download SandraSoft's benchmarking tools - download.com is a good place to start. There is quite a difference between SCSI controller interface speeds and actual trasfer speeds between the OS and the physical hard drive. The Interface speed is a theoretical max, and is more important when configuring several drives on a single controller channel - e.g. RAID 0, 0+1, 5, etc. If you have 4 drives on a channel configured as a 4 drive RAID 0 volume, the controller channel SCSI interface speed could be the rate-limiting-factor. (e.g. 4 drives with an *average* transfer rate of 25 MB/sec = 100 MB/sec 80 MB/sec). As there is a cache on the hard drive (2-4 MB is customary) and could be a cache on the RAID contoller (128 MB - 4 GB?) the channel should be saturated during memory to memory transfers (after negotiation for the transfer has taken place) - short bursts which are then slowed by the subsequent access of the phyiscal media. Typical sustained read/write speeds are on the order of 30 MB/sec on the latest and greatest 10,000 RPM drives. The fastest sustained read/write I've seen is here - is for the 15,000 RPM Seagate Cheetah - close to 50 MB/sec on the outer tracks http://www.storagereview.com/articles/200105/20010510ST373405LW_1.html Interfacespeed (MB/sec) SCSI Ultra Wide UW 40 Ultra2 WideU2W 80 Ultra160 U160 160 Ultra320 U320 320 IDE UDMA-33ATA-4 33 UDMA-66ATA-5 66 Ultra ATA ATA-6 100 Most likely, seek time will dominate transfer time unless you hike the operating system IO_size up from 64 KB. this site looks like fun: http://www.storagereview.com/cgi-bin/bench_compare.pl remember - little 'b' is bits, big 'B' is Bytes. This is extremely important if you happen to look at NAS - using Gigabit Ethernet for shared storage. Paul -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Paul Drake 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: Mohan, Ross 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: Scsi I/O speed
Ross, I love computers and I love tinckering with them to make them run sweetly, but I don't have a friggen CLUE about what you just wrote!:) Point me to the mythical paper where all of this vast knowledge and buzzwords came from and I will dive in:) KK -Original Message- Sent: Thursday, July 12, 2001 10:56 AM To: Multiple recipients of list ORACLE-L also, consider turning OFF command tag queueingcheck mobo drivers for i/o bus-related hwcheck w/t vice w/b cache, look at stripe stride vice os block size. Ross -Original Message- Sent: Wednesday, July 11, 2001 1:41 PM To: Multiple recipients of list ORACLE-L Kevin Kostyszyn wrote: Hi all, I was measuring the i/o performance of my scsi drives and I have a quick question that maybe someone could shed some light upon. Currently I am using Ultra 2/Wide scsi conrollers, this is supposed to have an I/O of 80mb/s. Well, when I perform the test all of the machines seem to be operation at halp of the max speed. One operates at about 20mb/s read and write and the others are even slower than that. Now on the first one, it is the only HD on the controller, on the others there are two disks. Even on my Ultra/160 it seems to be maxing out at 40 read and write. Am I missing something? Am I reading this the wrong way? Help:( Sincerely, Kevin Kostyszyn DBA Dulcian, Inc www.dulcian.com [EMAIL PROTECTED] Kevin, download SandraSoft's benchmarking tools - download.com is a good place to start. There is quite a difference between SCSI controller interface speeds and actual trasfer speeds between the OS and the physical hard drive. The Interface speed is a theoretical max, and is more important when configuring several drives on a single controller channel - e.g. RAID 0, 0+1, 5, etc. If you have 4 drives on a channel configured as a 4 drive RAID 0 volume, the controller channel SCSI interface speed could be the rate-limiting-factor. (e.g. 4 drives with an *average* transfer rate of 25 MB/sec = 100 MB/sec 80 MB/sec). As there is a cache on the hard drive (2-4 MB is customary) and could be a cache on the RAID contoller (128 MB - 4 GB?) the channel should be saturated during memory to memory transfers (after negotiation for the transfer has taken place) - short bursts which are then slowed by the subsequent access of the phyiscal media. Typical sustained read/write speeds are on the order of 30 MB/sec on the latest and greatest 10,000 RPM drives. The fastest sustained read/write I've seen is here - is for the 15,000 RPM Seagate Cheetah - close to 50 MB/sec on the outer tracks http://www.storagereview.com/articles/200105/20010510ST373405LW_1.html Interfacespeed (MB/sec) SCSI Ultra Wide UW 40 Ultra2 WideU2W 80 Ultra160 U160 160 Ultra320 U320 320 IDE UDMA-33ATA-4 33 UDMA-66ATA-5 66 Ultra ATA ATA-6 100 Most likely, seek time will dominate transfer time unless you hike the operating system IO_size up from 64 KB. this site looks like fun: http://www.storagereview.com/cgi-bin/bench_compare.pl remember - little 'b' is bits, big 'B' is Bytes. This is extremely important if you happen to look at NAS - using Gigabit Ethernet for shared storage. Paul -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Paul Drake 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: Mohan, Ross 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: Kevin Kostyszyn 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
RE: Scsi I/O speed
Buzzwords are great. There are a few good raid papers on my site that cover some of those he mentioned. w/t is write through cache w/b is write back cache Write back cache is basically battery backed up memory on the raid controller to provide exceptially high transactional rates. Stripe size is the size used when creating arrays, it detirmines how the scsi controller writes out to disks in stripes. OS block size is the obvious. Command tagging is when you allow the OS to send multiple scsi commands to the controller to execute parallel. This in theory reduces the need to awknowledge each request and execute it. Disconnect/reconnect support is another feature that allows the disk to disconnect to from the system when handling a load of requests. This generally reduces the bus utiliization. This is a very brief run down of the things mentioned. HTH, Walking on water and developing software from a specification are easy if both are frozen. Christopher R. Spence OCP MCSE MCP A+ RAPTOR CNA Oracle DBA Phone: (978) 322-5744 Fax:(707) 885-2275 Fuelspot 73 Princeton Street North, Chelmsford 01863 -Original Message- Sent: Thursday, July 12, 2001 12:21 PM To: Multiple recipients of list ORACLE-L Ross, I love computers and I love tinckering with them to make them run sweetly, but I don't have a friggen CLUE about what you just wrote!:) Point me to the mythical paper where all of this vast knowledge and buzzwords came from and I will dive in:) KK -Original Message- Sent: Thursday, July 12, 2001 10:56 AM To: Multiple recipients of list ORACLE-L also, consider turning OFF command tag queueingcheck mobo drivers for i/o bus-related hwcheck w/t vice w/b cache, look at stripe stride vice os block size. Ross -Original Message- Sent: Wednesday, July 11, 2001 1:41 PM To: Multiple recipients of list ORACLE-L Kevin Kostyszyn wrote: Hi all, I was measuring the i/o performance of my scsi drives and I have a quick question that maybe someone could shed some light upon. Currently I am using Ultra 2/Wide scsi conrollers, this is supposed to have an I/O of 80mb/s. Well, when I perform the test all of the machines seem to be operation at halp of the max speed. One operates at about 20mb/s read and write and the others are even slower than that. Now on the first one, it is the only HD on the controller, on the others there are two disks. Even on my Ultra/160 it seems to be maxing out at 40 read and write. Am I missing something? Am I reading this the wrong way? Help:( Sincerely, Kevin Kostyszyn DBA Dulcian, Inc www.dulcian.com [EMAIL PROTECTED] Kevin, download SandraSoft's benchmarking tools - download.com is a good place to start. There is quite a difference between SCSI controller interface speeds and actual trasfer speeds between the OS and the physical hard drive. The Interface speed is a theoretical max, and is more important when configuring several drives on a single controller channel - e.g. RAID 0, 0+1, 5, etc. If you have 4 drives on a channel configured as a 4 drive RAID 0 volume, the controller channel SCSI interface speed could be the rate-limiting-factor. (e.g. 4 drives with an *average* transfer rate of 25 MB/sec = 100 MB/sec 80 MB/sec). As there is a cache on the hard drive (2-4 MB is customary) and could be a cache on the RAID contoller (128 MB - 4 GB?) the channel should be saturated during memory to memory transfers (after negotiation for the transfer has taken place) - short bursts which are then slowed by the subsequent access of the phyiscal media. Typical sustained read/write speeds are on the order of 30 MB/sec on the latest and greatest 10,000 RPM drives. The fastest sustained read/write I've seen is here - is for the 15,000 RPM Seagate Cheetah - close to 50 MB/sec on the outer tracks http://www.storagereview.com/articles/200105/20010510ST373405LW_1.html Interfacespeed (MB/sec) SCSI Ultra Wide UW 40 Ultra2 WideU2W 80 Ultra160 U160 160 Ultra320 U320 320 IDE UDMA-33ATA-4 33 UDMA-66ATA-5 66 Ultra ATA ATA-6 100 Most likely, seek time will dominate transfer time unless you hike the operating system IO_size up from 64 KB. this site looks like fun: http://www.storagereview.com/cgi-bin/bench_compare.pl remember - little 'b' is bits, big 'B' is Bytes. This is extremely important if you happen to look at NAS - using Gigabit Ethernet for shared storage. Paul -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Paul Drake 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
RE: Scsi I/O speed
Thanks Chris! I will have to look at your site, what is the URL? Is there information to check on w/b w/t cache settings? Isn't one of them better than the other? Also, this is not a RAID system, just a couple of SCSI's hangin out and being beat on. KK -Original Message- Spence Sent: Thursday, July 12, 2001 1:30 PM To: Multiple recipients of list ORACLE-L Buzzwords are great. There are a few good raid papers on my site that cover some of those he mentioned. w/t is write through cache w/b is write back cache Write back cache is basically battery backed up memory on the raid controller to provide exceptially high transactional rates. Stripe size is the size used when creating arrays, it detirmines how the scsi controller writes out to disks in stripes. OS block size is the obvious. Command tagging is when you allow the OS to send multiple scsi commands to the controller to execute parallel. This in theory reduces the need to awknowledge each request and execute it. Disconnect/reconnect support is another feature that allows the disk to disconnect to from the system when handling a load of requests. This generally reduces the bus utiliization. This is a very brief run down of the things mentioned. HTH, Walking on water and developing software from a specification are easy if both are frozen. Christopher R. Spence OCP MCSE MCP A+ RAPTOR CNA Oracle DBA Phone: (978) 322-5744 Fax:(707) 885-2275 Fuelspot 73 Princeton Street North, Chelmsford 01863 -Original Message- Sent: Thursday, July 12, 2001 12:21 PM To: Multiple recipients of list ORACLE-L Ross, I love computers and I love tinckering with them to make them run sweetly, but I don't have a friggen CLUE about what you just wrote!:) Point me to the mythical paper where all of this vast knowledge and buzzwords came from and I will dive in:) KK -Original Message- Sent: Thursday, July 12, 2001 10:56 AM To: Multiple recipients of list ORACLE-L also, consider turning OFF command tag queueingcheck mobo drivers for i/o bus-related hwcheck w/t vice w/b cache, look at stripe stride vice os block size. Ross -Original Message- Sent: Wednesday, July 11, 2001 1:41 PM To: Multiple recipients of list ORACLE-L Kevin Kostyszyn wrote: Hi all, I was measuring the i/o performance of my scsi drives and I have a quick question that maybe someone could shed some light upon. Currently I am using Ultra 2/Wide scsi conrollers, this is supposed to have an I/O of 80mb/s. Well, when I perform the test all of the machines seem to be operation at halp of the max speed. One operates at about 20mb/s read and write and the others are even slower than that. Now on the first one, it is the only HD on the controller, on the others there are two disks. Even on my Ultra/160 it seems to be maxing out at 40 read and write. Am I missing something? Am I reading this the wrong way? Help:( Sincerely, Kevin Kostyszyn DBA Dulcian, Inc www.dulcian.com [EMAIL PROTECTED] Kevin, download SandraSoft's benchmarking tools - download.com is a good place to start. There is quite a difference between SCSI controller interface speeds and actual trasfer speeds between the OS and the physical hard drive. The Interface speed is a theoretical max, and is more important when configuring several drives on a single controller channel - e.g. RAID 0, 0+1, 5, etc. If you have 4 drives on a channel configured as a 4 drive RAID 0 volume, the controller channel SCSI interface speed could be the rate-limiting-factor. (e.g. 4 drives with an *average* transfer rate of 25 MB/sec = 100 MB/sec 80 MB/sec). As there is a cache on the hard drive (2-4 MB is customary) and could be a cache on the RAID contoller (128 MB - 4 GB?) the channel should be saturated during memory to memory transfers (after negotiation for the transfer has taken place) - short bursts which are then slowed by the subsequent access of the phyiscal media. Typical sustained read/write speeds are on the order of 30 MB/sec on the latest and greatest 10,000 RPM drives. The fastest sustained read/write I've seen is here - is for the 15,000 RPM Seagate Cheetah - close to 50 MB/sec on the outer tracks http://www.storagereview.com/articles/200105/20010510ST373405LW_1.html Interfacespeed (MB/sec) SCSI Ultra Wide UW 40 Ultra2 WideU2W 80 Ultra160 U160 160 Ultra320 U320 320 IDE UDMA-33ATA-4 33 UDMA-66ATA-5 66 Ultra ATA ATA-6 100 Most likely, seek time will dominate transfer time unless you hike the operating system IO_size up from 64 KB. this site looks like fun: http://www.storagereview.com/cgi-bin/bench_compare.pl remember - little 'b' is bits, big 'B' is Bytes. This is extremely important if you happen to look at NAS - using Gigabit Ethernet for shared storage. Paul -- Please see the official ORACLE-L FAQ:
RE: Scsi I/O speed
www.vampired.net Write-back cache is much faster. Basically the OS sends an IO request to the controller, it places the change in the battery backed up memory and responds complete to the OS. At this point the transaction is done. Later (ussually seconds) the IO is written to the disks. This proves to provide very fast response time due to the quick return to the OS, it also proves very quick as IO is handled in larger chunks which takes advantage of the higher IO rates as well as provides very good use of the stripe size to fully utiliize the stripe width of a volume rather than sending it small IO's and only using few disks. Write-through simply means the controller will not claim transaction complete until the disks have stored the information. This is generally due to the lack of battery backed up ram. Battery backuped ram gives you the protection of power loss to finish the transactions on startup. Which is why you can give the quick return to the OS safely. There are a few articles on my site on Raid which covers a lot of scsi technology. You will find them all under Concepts sections under Articles. The RAID Awakinging is a good article that covers write-back cache if I remember correctly. -Original Message- Sent: Thursday, July 12, 2001 1:42 PM To: Multiple recipients of list ORACLE-L Thanks Chris! I will have to look at your site, what is the URL? Is there information to check on w/b w/t cache settings? Isn't one of them better than the other? Also, this is not a RAID system, just a couple of SCSI's hangin out and being beat on. KK -Original Message- Spence Sent: Thursday, July 12, 2001 1:30 PM To: Multiple recipients of list ORACLE-L Buzzwords are great. There are a few good raid papers on my site that cover some of those he mentioned. w/t is write through cache w/b is write back cache Write back cache is basically battery backed up memory on the raid controller to provide exceptially high transactional rates. Stripe size is the size used when creating arrays, it detirmines how the scsi controller writes out to disks in stripes. OS block size is the obvious. Command tagging is when you allow the OS to send multiple scsi commands to the controller to execute parallel. This in theory reduces the need to awknowledge each request and execute it. Disconnect/reconnect support is another feature that allows the disk to disconnect to from the system when handling a load of requests. This generally reduces the bus utiliization. This is a very brief run down of the things mentioned. HTH, Walking on water and developing software from a specification are easy if both are frozen. Christopher R. Spence OCP MCSE MCP A+ RAPTOR CNA Oracle DBA Phone: (978) 322-5744 Fax:(707) 885-2275 Fuelspot 73 Princeton Street North, Chelmsford 01863 -Original Message- Sent: Thursday, July 12, 2001 12:21 PM To: Multiple recipients of list ORACLE-L Ross, I love computers and I love tinckering with them to make them run sweetly, but I don't have a friggen CLUE about what you just wrote!:) Point me to the mythical paper where all of this vast knowledge and buzzwords came from and I will dive in:) KK -Original Message- Sent: Thursday, July 12, 2001 10:56 AM To: Multiple recipients of list ORACLE-L also, consider turning OFF command tag queueingcheck mobo drivers for i/o bus-related hwcheck w/t vice w/b cache, look at stripe stride vice os block size. Ross -Original Message- Sent: Wednesday, July 11, 2001 1:41 PM To: Multiple recipients of list ORACLE-L Kevin Kostyszyn wrote: Hi all, I was measuring the i/o performance of my scsi drives and I have a quick question that maybe someone could shed some light upon. Currently I am using Ultra 2/Wide scsi conrollers, this is supposed to have an I/O of 80mb/s. Well, when I perform the test all of the machines seem to be operation at halp of the max speed. One operates at about 20mb/s read and write and the others are even slower than that. Now on the first one, it is the only HD on the controller, on the others there are two disks. Even on my Ultra/160 it seems to be maxing out at 40 read and write. Am I missing something? Am I reading this the wrong way? Help:( Sincerely, Kevin Kostyszyn DBA Dulcian, Inc www.dulcian.com [EMAIL PROTECTED] Kevin, download SandraSoft's benchmarking tools - download.com is a good place to start. There is quite a difference between SCSI controller interface speeds and actual trasfer speeds between the OS and the physical hard drive. The Interface speed is a theoretical max, and is more important when configuring several drives on a single controller channel - e.g. RAID 0, 0+1, 5, etc. If you have 4 drives on a channel configured as a 4 drive RAID 0 volume, the controller channel SCSI interface speed could be the rate-limiting-factor. (e.g. 4 drives with an *average* transfer rate of 25
RE: Scsi I/O speed
Thanks for the translate, Chris. I must have had too little caffeine this morning! -Original Message- Sent: Thursday, July 12, 2001 1:30 PM To: Multiple recipients of list ORACLE-L Buzzwords are great. There are a few good raid papers on my site that cover some of those he mentioned. w/t is write through cache w/b is write back cache Write back cache is basically battery backed up memory on the raid controller to provide exceptially high transactional rates. Stripe size is the size used when creating arrays, it detirmines how the scsi controller writes out to disks in stripes. OS block size is the obvious. Command tagging is when you allow the OS to send multiple scsi commands to the controller to execute parallel. This in theory reduces the need to awknowledge each request and execute it. Disconnect/reconnect support is another feature that allows the disk to disconnect to from the system when handling a load of requests. This generally reduces the bus utiliization. This is a very brief run down of the things mentioned. HTH, Walking on water and developing software from a specification are easy if both are frozen. Christopher R. Spence OCP MCSE MCP A+ RAPTOR CNA Oracle DBA Phone: (978) 322-5744 Fax:(707) 885-2275 Fuelspot 73 Princeton Street North, Chelmsford 01863 -Original Message- Sent: Thursday, July 12, 2001 12:21 PM To: Multiple recipients of list ORACLE-L Ross, I love computers and I love tinckering with them to make them run sweetly, but I don't have a friggen CLUE about what you just wrote!:) Point me to the mythical paper where all of this vast knowledge and buzzwords came from and I will dive in:) KK -Original Message- Sent: Thursday, July 12, 2001 10:56 AM To: Multiple recipients of list ORACLE-L also, consider turning OFF command tag queueingcheck mobo drivers for i/o bus-related hwcheck w/t vice w/b cache, look at stripe stride vice os block size. Ross -Original Message- Sent: Wednesday, July 11, 2001 1:41 PM To: Multiple recipients of list ORACLE-L Kevin Kostyszyn wrote: Hi all, I was measuring the i/o performance of my scsi drives and I have a quick question that maybe someone could shed some light upon. Currently I am using Ultra 2/Wide scsi conrollers, this is supposed to have an I/O of 80mb/s. Well, when I perform the test all of the machines seem to be operation at halp of the max speed. One operates at about 20mb/s read and write and the others are even slower than that. Now on the first one, it is the only HD on the controller, on the others there are two disks. Even on my Ultra/160 it seems to be maxing out at 40 read and write. Am I missing something? Am I reading this the wrong way? Help:( Sincerely, Kevin Kostyszyn DBA Dulcian, Inc www.dulcian.com [EMAIL PROTECTED] Kevin, download SandraSoft's benchmarking tools - download.com is a good place to start. There is quite a difference between SCSI controller interface speeds and actual trasfer speeds between the OS and the physical hard drive. The Interface speed is a theoretical max, and is more important when configuring several drives on a single controller channel - e.g. RAID 0, 0+1, 5, etc. If you have 4 drives on a channel configured as a 4 drive RAID 0 volume, the controller channel SCSI interface speed could be the rate-limiting-factor. (e.g. 4 drives with an *average* transfer rate of 25 MB/sec = 100 MB/sec 80 MB/sec). As there is a cache on the hard drive (2-4 MB is customary) and could be a cache on the RAID contoller (128 MB - 4 GB?) the channel should be saturated during memory to memory transfers (after negotiation for the transfer has taken place) - short bursts which are then slowed by the subsequent access of the phyiscal media. Typical sustained read/write speeds are on the order of 30 MB/sec on the latest and greatest 10,000 RPM drives. The fastest sustained read/write I've seen is here - is for the 15,000 RPM Seagate Cheetah - close to 50 MB/sec on the outer tracks http://www.storagereview.com/articles/200105/20010510ST373405LW_1.html Interfacespeed (MB/sec) SCSI Ultra Wide UW 40 Ultra2 WideU2W 80 Ultra160 U160 160 Ultra320 U320 320 IDE UDMA-33ATA-4 33 UDMA-66ATA-5 66 Ultra ATA ATA-6 100 Most likely, seek time will dominate transfer time unless you hike the operating system IO_size up from 64 KB. this site looks like fun: http://www.storagereview.com/cgi-bin/bench_compare.pl remember - little 'b' is bits, big 'B' is Bytes. This is extremely important if you happen to look at NAS - using Gigabit Ethernet for shared storage. Paul -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Paul Drake INET: [EMAIL PROTECTED] Fat City Network Services-- (858) 538-5051 FAX: (858) 538-5051 San Diego, California-- Public Internet
Re: Scsi I/O speed
Your questions are good ones... Driver issues may exist. Contact adaptec, or scsi card maker. - jeremy -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: 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: Scsi I/O speed
Kevin Kostyszyn wrote: Hi all, I was measuring the i/o performance of my scsi drives and I have a quick question that maybe someone could shed some light upon. Currently I am using Ultra 2/Wide scsi conrollers, this is supposed to have an I/O of 80mb/s. Well, when I perform the test all of the machines seem to be operation at halp of the max speed. One operates at about 20mb/s read and write and the others are even slower than that. Now on the first one, it is the only HD on the controller, on the others there are two disks. Even on my Ultra/160 it seems to be maxing out at 40 read and write. Am I missing something? Am I reading this the wrong way? Help:( Sincerely, Kevin Kostyszyn DBA Dulcian, Inc www.dulcian.com [EMAIL PROTECTED] Kevin, download SandraSoft's benchmarking tools - download.com is a good place to start. There is quite a difference between SCSI controller interface speeds and actual trasfer speeds between the OS and the physical hard drive. The Interface speed is a theoretical max, and is more important when configuring several drives on a single controller channel - e.g. RAID 0, 0+1, 5, etc. If you have 4 drives on a channel configured as a 4 drive RAID 0 volume, the controller channel SCSI interface speed could be the rate-limiting-factor. (e.g. 4 drives with an *average* transfer rate of 25 MB/sec = 100 MB/sec 80 MB/sec). As there is a cache on the hard drive (2-4 MB is customary) and could be a cache on the RAID contoller (128 MB - 4 GB?) the channel should be saturated during memory to memory transfers (after negotiation for the transfer has taken place) - short bursts which are then slowed by the subsequent access of the phyiscal media. Typical sustained read/write speeds are on the order of 30 MB/sec on the latest and greatest 10,000 RPM drives. The fastest sustained read/write I've seen is here - is for the 15,000 RPM Seagate Cheetah - close to 50 MB/sec on the outer tracks http://www.storagereview.com/articles/200105/20010510ST373405LW_1.html Interfacespeed (MB/sec) SCSI Ultra Wide UW 40 Ultra2 WideU2W 80 Ultra160 U160 160 Ultra320 U320 320 IDE UDMA-33ATA-4 33 UDMA-66ATA-5 66 Ultra ATA ATA-6 100 Most likely, seek time will dominate transfer time unless you hike the operating system IO_size up from 64 KB. this site looks like fun: http://www.storagereview.com/cgi-bin/bench_compare.pl remember - little 'b' is bits, big 'B' is Bytes. This is extremely important if you happen to look at NAS - using Gigabit Ethernet for shared storage. Paul -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Paul Drake 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: Scsi I/O speed
Kevin, One thing to remember with SCSI...it's not necessarily the speed of the controller that matters. The SCSI bus will be slowed down to the speed of the slowest device in the chain...or on the bus. For example, if you have a controller with 80mb/s and 3 HDs with 80mb/s and 1 HD at 40mb/s...all running off the same controller...the bus speed will be no more than 40mb/s (the speed of the slowest device). Again, that is the theoretical max speed. Ed -Original Message- Sent: Wednesday, July 11, 2001 12:22 PM To: Multiple recipients of list ORACLE-L Hi all, I was measuring the i/o performance of my scsi drives and I have a quick question that maybe someone could shed some light upon. Currently I am using Ultra 2/Wide scsi conrollers, this is supposed to have an I/O of 80mb/s. Well, when I perform the test all of the machines seem to be operation at halp of the max speed. One operates at about 20mb/s read and write and the others are even slower than that. Now on the first one, it is the only HD on the controller, on the others there are two disks. Even on my Ultra/160 it seems to be maxing out at 40 read and write. Am I missing something? Am I reading this the wrong way? Help:( Sincerely, Kevin Kostyszyn DBA Dulcian, Inc www.dulcian.com [EMAIL PROTECTED] -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Kevin Kostyszyn 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: Haskins, Ed 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: Scsi I/O speed
Well yeah, all of this makes perfect sense to me. However, if I am testing the devices I would assume that the test software is going to send as much info as it can down the pipe, you know stuff it. With the Ultra/160 I am assuming that there is only a 80mb/s drive in there, I never opened it up and looked, but I will now. I will use a couple different utilities and see if the rates are the same. Also, I know that the drives I have in these machines are all 80mb/s drives, at least in the other machines, so there shouldn't be any device that is bringing down the rate. I don't know, but I would love to try and iprove this rate. KK -Original Message- Sent: Wednesday, July 11, 2001 2:00 PM To: Multiple recipients of list ORACLE-L Kevin, One thing to remember with SCSI...it's not necessarily the speed of the controller that matters. The SCSI bus will be slowed down to the speed of the slowest device in the chain...or on the bus. For example, if you have a controller with 80mb/s and 3 HDs with 80mb/s and 1 HD at 40mb/s...all running off the same controller...the bus speed will be no more than 40mb/s (the speed of the slowest device). Again, that is the theoretical max speed. Ed -Original Message- Sent: Wednesday, July 11, 2001 12:22 PM To: Multiple recipients of list ORACLE-L Hi all, I was measuring the i/o performance of my scsi drives and I have a quick question that maybe someone could shed some light upon. Currently I am using Ultra 2/Wide scsi conrollers, this is supposed to have an I/O of 80mb/s. Well, when I perform the test all of the machines seem to be operation at halp of the max speed. One operates at about 20mb/s read and write and the others are even slower than that. Now on the first one, it is the only HD on the controller, on the others there are two disks. Even on my Ultra/160 it seems to be maxing out at 40 read and write. Am I missing something? Am I reading this the wrong way? Help:( Sincerely, Kevin Kostyszyn DBA Dulcian, Inc www.dulcian.com [EMAIL PROTECTED] -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Kevin Kostyszyn 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: Haskins, Ed 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: Kevin Kostyszyn 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: Scsi I/O speed
Kev, Make sure that the SCSI CD-ROM or Tape Drive aren't connected to this controller. Ed -Original Message- Sent: Wednesday, July 11, 2001 2:56 PM To: Multiple recipients of list ORACLE-L Well yeah, all of this makes perfect sense to me. However, if I am testing the devices I would assume that the test software is going to send as much info as it can down the pipe, you know stuff it. With the Ultra/160 I am assuming that there is only a 80mb/s drive in there, I never opened it up and looked, but I will now. I will use a couple different utilities and see if the rates are the same. Also, I know that the drives I have in these machines are all 80mb/s drives, at least in the other machines, so there shouldn't be any device that is bringing down the rate. I don't know, but I would love to try and iprove this rate. KK -Original Message- Sent: Wednesday, July 11, 2001 2:00 PM To: Multiple recipients of list ORACLE-L Kevin, One thing to remember with SCSI...it's not necessarily the speed of the controller that matters. The SCSI bus will be slowed down to the speed of the slowest device in the chain...or on the bus. For example, if you have a controller with 80mb/s and 3 HDs with 80mb/s and 1 HD at 40mb/s...all running off the same controller...the bus speed will be no more than 40mb/s (the speed of the slowest device). Again, that is the theoretical max speed. Ed -Original Message- Sent: Wednesday, July 11, 2001 12:22 PM To: Multiple recipients of list ORACLE-L Hi all, I was measuring the i/o performance of my scsi drives and I have a quick question that maybe someone could shed some light upon. Currently I am using Ultra 2/Wide scsi conrollers, this is supposed to have an I/O of 80mb/s. Well, when I perform the test all of the machines seem to be operation at halp of the max speed. One operates at about 20mb/s read and write and the others are even slower than that. Now on the first one, it is the only HD on the controller, on the others there are two disks. Even on my Ultra/160 it seems to be maxing out at 40 read and write. Am I missing something? Am I reading this the wrong way? Help:( Sincerely, Kevin Kostyszyn DBA Dulcian, Inc www.dulcian.com [EMAIL PROTECTED] -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Kevin Kostyszyn 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: Haskins, Ed 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: Kevin Kostyszyn 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: Haskins, Ed 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: Scsi I/O speed
They are not, two different controllers. -Original Message- Sent: Wednesday, July 11, 2001 3:51 PM To: Multiple recipients of list ORACLE-L Kev, Make sure that the SCSI CD-ROM or Tape Drive aren't connected to this controller. Ed -Original Message- Sent: Wednesday, July 11, 2001 2:56 PM To: Multiple recipients of list ORACLE-L Well yeah, all of this makes perfect sense to me. However, if I am testing the devices I would assume that the test software is going to send as much info as it can down the pipe, you know stuff it. With the Ultra/160 I am assuming that there is only a 80mb/s drive in there, I never opened it up and looked, but I will now. I will use a couple different utilities and see if the rates are the same. Also, I know that the drives I have in these machines are all 80mb/s drives, at least in the other machines, so there shouldn't be any device that is bringing down the rate. I don't know, but I would love to try and iprove this rate. KK -Original Message- Sent: Wednesday, July 11, 2001 2:00 PM To: Multiple recipients of list ORACLE-L Kevin, One thing to remember with SCSI...it's not necessarily the speed of the controller that matters. The SCSI bus will be slowed down to the speed of the slowest device in the chain...or on the bus. For example, if you have a controller with 80mb/s and 3 HDs with 80mb/s and 1 HD at 40mb/s...all running off the same controller...the bus speed will be no more than 40mb/s (the speed of the slowest device). Again, that is the theoretical max speed. Ed -Original Message- Sent: Wednesday, July 11, 2001 12:22 PM To: Multiple recipients of list ORACLE-L Hi all, I was measuring the i/o performance of my scsi drives and I have a quick question that maybe someone could shed some light upon. Currently I am using Ultra 2/Wide scsi conrollers, this is supposed to have an I/O of 80mb/s. Well, when I perform the test all of the machines seem to be operation at halp of the max speed. One operates at about 20mb/s read and write and the others are even slower than that. Now on the first one, it is the only HD on the controller, on the others there are two disks. Even on my Ultra/160 it seems to be maxing out at 40 read and write. Am I missing something? Am I reading this the wrong way? Help:( Sincerely, Kevin Kostyszyn DBA Dulcian, Inc www.dulcian.com [EMAIL PROTECTED] -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Kevin Kostyszyn 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: Haskins, Ed 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: Kevin Kostyszyn 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: Haskins, Ed 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
