RE: Why would anyone install Exchange on a PDC?

[Ben Winzenz]

Title: RE: Why would anyone install Exchange on a PDC?

How does a RAID 1 (mirroring) not keep you running in the event of a failure?  I'm curious.  It most certainly IS fault-tolerant.  If you lose a disk from RAID 1, you are still running.  You don't HAVE to run maintenance until you decide to.  Now, certainly, it would be idiotic NOT to replace the failed disk right away and break/re-create the mirror, but with newer RAID controllers, you can even do this online.  RAID 5 will give you the EXACT same downtime.  You replace the dead drive, and you wait while your RAID controller rebuilds the stripe set.  But again, what is the difference between the 2 in terms of time?  What, a couple of minutes?  I do concede that AS LONG as your databases and log files are kept on separate spindles, then I personally don't care whether you use RAID 1 or 5.  Replaying the log files comes into play when you restore the database from tape backup.  I don't think it applies to creating a new database.  Circular logging IS on by default, but most Exchange admins with experience (meaning those that know about Exchange and its features and why certain features are used and why others aren't) turn that feature off as one of the first steps once they build a server.   Ben Winzenz, MCSE Network/Systems Administrator Peregrine Systems   -----Original Message----- From: MHR(Michael Ross) [mailto:[EMAIL PROTECTED]] Sent: Friday, February 22, 2002 11:12 AM To: MS-Exchange Admin Issues Subject: RE: Why would anyone install Exchange on a PDC?   My whole point is.. Why ever use anything less than a RAID 5, (unless something like Oracle NEEDS it), on a production box when a RAID 5 configuration can keep ya running in the event of a disk failure. Youre talking the cost of 1 disk.. Whats that in comparision to the time it takes you to break the mirror, replace the disk, and recreate the mirror? If I got a -1018 error, Id attempt to repair the DB, the exmerge the data out.. Create a new DB and exmerge the data back in.. Ive done with with PSS on the phone twice due to the cluster we HAD screwing up the DB. It didn't matter that our log files were on the RAID 1 partition or on the disk where the DB was. Cirular logging is enabled by default on Exchange 5.5.. You have to disable it to reap those benefits. -----Original Message----- From: Neil Hobson [mailto:[EMAIL PROTECTED]] Sent: Friday, February 22, 2002 10:03 AM To: MS-Exchange Admin Issues Subject: RE: Why would anyone install Exchange on a PDC?   Circular logging doesn't come into it.  You simply wouldn't use it on a mailbox server. The difference is simple:  scenario 1 means you lose that day's email, scenario 2 you don't.  In scenario 1, if you lose 2 disks, you ain't gonna have your log files.  Also, with a -1018 error, I wouldn't bother attempting to repair the database.  Would you seriously use eseutil /p on a production database?  The recommended method is to restore from backup (after fixing the hardware problem) or restore the backup to alternative hardware. Why RAID1?  Well, the best practises have always been to use a separate drive for the logs that perform sequential I/O in an optimal fashion. RAID1 meets this requirement.  For servers with large numbers of users, this is an issue.  And if you lose a drive in a RAID1 array, well, you've still got your data intact. Yes, you could use RAID5.  But why use 3 disks when 2 will do the job, even if performance is not an issue?   Neil Hobson Silversands http://www.silversands.co.uk Microsoft Gold Certified Partner For Enterprise Systems For Collaborative Solutions -----Original Message----- From: MHR(Michael Ross) [mailto:[EMAIL PROTECTED]] Posted At: 22 February 2002 15:44 Posted To: Sunbelt Exchange List Conversation: Why would anyone install Exchange on a PDC? Subject: RE: Why would anyone install Exchange on a PDC?   The difference is you don't use Circular logging,and you backup your logfiles AND your exchange DB.. You can then get back to the point of failure.. If you have your logfiles, and your disk is still running, you can repair the Db and be back up and running to the point of failure. Even if youre idea is better.. Why a RAID 1? Why not a RAID 5? What happens when youre RAID1 logfile loses a member of the mirror? -----Original Message----- From: Neil Hobson [mailto:[EMAIL PROTECTED]] Sent: Friday, February 22, 2002 9:37 AM To: MS-Exchange Admin Issues Subject: RE: Why would anyone install Exchange on a PDC?   Scenario 1: Your logs and databases are both on the same RAID5 array. Your last full online backup was last night at 11pm. Today, at 4pm, your database gets corrupt.  Say you notice a -1018, or two disks in the RAID5 array have failed, or whatever. All you therefore have is last night's backup.  Tell me, what does that mean? Scenario 2: The same as scenario 1, except your logs are on a separate RAID1 array. You therefore have last night's backup, plus the transaction logs. What's the difference now? Neil Hobson Silversands http://www.silversands.co.uk Microsoft Gold Certified Partner For Enterprise Systems For Collaborative Solutions   -----Original Message----- From: MHR(Michael Ross) [mailto:[EMAIL PROTECTED]] Posted At: 22 February 2002 15:29 Posted To: Sunbelt Exchange List Conversation: Why would anyone install Exchange on a PDC? Subject: RE: Why would anyone install Exchange on a PDC?   Can you quote the reasons for it. I honestly don't see any other reason to put Log files on a Mirrored partition. Its not fault tolerant.. At least not on the fly.. If 1 drive fails, ya gotta break the mirror.. If its RAID 5, it will still run. If its not a performance issue to put them on their own Mirrored partition, why would you do it? Is it just to keep them safe in case your database drive goes down? If that happens, youre still Skrewed.... -----Original Message----- From: Neil Hobson [mailto:[EMAIL PROTECTED]] Sent: Friday, February 22, 2002 9:18 AM To: MS-Exchange Admin Issues Subject: RE: Why would anyone install Exchange on a PDC?   The primary reason for putting logs on their own drive is not a performance reason.   Neil Hobson Silversands http://www.silversands.co.uk Microsoft Gold Certified Partner For Enterprise Systems For Collaborative Solutions -----Original Message----- From: MHR(Michael Ross) [mailto:[EMAIL PROTECTED]] Posted At: 22 February 2002 15:14 Posted To: Sunbelt Exchange List Conversation: Why would anyone install Exchange on a PDC? Subject: RE: Why would anyone install Exchange on a PDC?   I would put exchange and your pdc on a Dual PIII 733 MHZ processor ..minimum.. With at least 1 GB of RAM and no less than 40 GB of RAID 5 storage. Ive run Exchange on the RAID1 for logs, RAID 1 for OS and RAID 5 for the database specs.. And I see NO increase in peformance than if it was all on a RAID 5 partition.   -----Original Message----- From: Majetic, John RAME [mailto:[EMAIL PROTECTED]] Sent: Friday, February 22, 2002 9:02 AM To: MS-Exchange Admin Issues Subject: RE: Why would anyone install Exchange on a PDC?   I had our exchange server on an Pentium Pro 100 HP net sever with 196 MB of ram for about the first year we used exchange. It was the PDC, DHCP Server, Primary WINS, Ras server with 8 VPN ports and the exchange server with 180 boxes on it. Processor utilization rarely got above 50 percent. Lack of Hard Drive space, and memory, 196 MB was max for that box, were the reasons I took exchange off of it. Microsoft says you should have one domain controller for each 10000 accounts if I remember correctly, and this was written in the days of Pentium Pro 100s being a kick butt machine. Unless you have thousands of users I really don't see the domain controller resource drain a bar to putting an exchange box on a PDC. However I would not recommend putting it on a box with anything else. It was a real bitch having to take down the DHCP for a day when I had to clean out the I Love you virus. John Majetic -----Original Message----- From: Allen Crawford [mailto:[EMAIL PROTECTED]] Sent: Friday, February 22, 2002 9:31 AM To: MS-Exchange Admin Issues Subject: RE: Why would anyone install Exchange on a PDC?   Wow, I thought my PDC (P133 with 128MB of RAM) was bad...  -----Original Message----- From:   William Lefkovics [mailto:[EMAIL PROTECTED]] Sent:   Thursday, February 21, 2002 6:07 PM To:     MS-Exchange Admin Issues Subject:        RE: Why would anyone install Exchange on a PDC? Dude... I upgraded our PDC from a P75 to a P133 32MB RAM that's still in production. IF you can afford Exchange, you can afford a cheap BDC. I applaud your dedication to those companies.   -----Original Message----- From: Clark, Steve [mailto:[EMAIL PROTECTED]] Sent: Thursday, February 21, 2002 1:25 PM To: MS-Exchange Admin Issues Subject: RE: Why would anyone install Exchange on a PDC?   In the majority of shops I manage - there is no choice. Single server shops where the cost to have a BDC or even MS is over the budget. Keep in mind - the hardware is only a SMALL part of the cost. Most of the shops don't do Exchange - they go for POP mail. However, when the problem of shared contacts and calendars rears it's ugly head - Exchange is the solution. Steve Clark Clark Systems Support, LLC AVIEN Charter Member "Who's watching your network?" www.clarksupport.com         301-610-9584 voice         240-465-0323 Efax   The data furnished in connection with this document is deemed by Clark Systems Support, LLC., to contain proprietary and privileged information and shall not be disclosed or used for the benefit of others without the prior written permission of Clark Systems Support, LLC.   -----Original Message----- From: William Lefkovics [mailto:[EMAIL PROTECTED]] Sent: Thursday, February 21, 2002 4:22 PM To: MS-Exchange Admin Issues Subject: RE: Why would anyone install Exchange on a PDC? I will always advise not to, but it works fine.  The reasons not to: performance - not as big an issue today due to beefier machines recoverability - you better have a good BDC somewhere or tears are gonna fall. William -----Original Message----- From: Kevin Kennedy [mailto:[EMAIL PROTECTED]] Sent: Thursday, February 21, 2002 1:18 PM To: MS-Exchange Admin Issues Subject: Why would anyone install Exchange on a PDC?   Cost?  Whenever possible install Exchange on a stand alone server. Kevin Kennedy (K2) Network Administrator Mahi Networks, Inc. 707-283-1336   List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual to whom it is addressed. Any view or opinions presented are solely those of the author and do not necessarily represent those of Silversands, or any of its subsidiary companies. If you have received this email in error, please contact our Support Desk immediately by telephone on 01202-360000 or via email at [EMAIL PROTECTED] ********************************************************************** List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual to whom it is addressed. Any view or opinions presented are solely those of the author and do not necessarily represent those of Silversands, or any of its subsidiary companies. If you have received this email in error, please contact our Support Desk immediately by telephone on 01202-360000 or via email at [EMAIL PROTECTED] ********************************************************************** List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual to whom it is addressed. Any view or opinions presented are solely those of the author and do not necessarily represent those of Silversands, or any of its subsidiary companies. If you have received this email in error, please contact our Support Desk immediately by telephone on 01202-360000 or via email at [EMAIL PROTECTED] ********************************************************************** List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm