Hi Shawn: The biggest bottleneck will be seek times on the drives. Yes, sharing the same bus will slow things down, but adding further seeks by combining the logs and database on one spindle set will have a much greater impact. So, although there is only one SCSI bus to work with, I'd still create separate arrays.
Hi Devan: One other option you might consider which I use extensively, is to use one 18GB mirror set for both OS and logs, and put the remaining 4 drives into RAID 5 for Exchange databases and other randomly read/written data. You can logically partition the mirror set into two logical drive letters if you want to sandbox the OS. So, drives C: (for the OS) and E: (for the logs) are both on the mirror set. Drive F is on the RAID 5 set. (D: is CDRom) Once the OS loads, there should be minimal activity on drive C: (competing with Log writes on E:). If you are concerned about paging, move the page file to drive F:. If you are really anal about things, move the OS Event and other logs to drive F: as well. This isn't ideal, but it's a good compromise if you need to maximize your disk utilization yet still have complete fault tolerance and some modest performance gains (as opposed to using a single spindle set for everything). HTH, Linton -----Original Message----- From: [EMAIL PROTECTED] [mailto:Shawn.Hayes@;compass.net] Sent: Monday, October 21, 2002 4:27 PM To: [EMAIL PROTECTED] Subject: RE: [ActiveDir] RAID Configuration on DC's Part 3 Please explain how you will gain any performance increases when all three of your arrays exist on the same SCSI channel. Seems to me you have a single pipe leading to and from multiple arrays. It is not hard to figure where the bottle neck will be. -----Original Message----- From: Devan Pala [mailto:dpala@;hotmail.com] Sent: Monday, October 21, 2002 4:15 PM To: [EMAIL PROTECTED] Subject: [ActiveDir] RAID Configuration on DC's Part 3 Hi, Thanks for all your replies earlier. Yes, it is true that the server only has 6 drive bays. The array controller has 2 internal and 2 external ports but I can only use one internally since the 6 drive bays only terminate to one SCSI port. (in this particular server). Reason for buying the high-end controller is due to standards and a proven track record in production. Reason for not upgrading the chassis is primarily cost especially in the branch offices, the root and hub-site controllers are and will be configured entirely different, dual array controllers, quad-xeon processors etc. The whole nine yards. The database has been sized and definitely over-engineered for the approx. 2500 users spread over 15 sites in the Americas and Europe. I do understand that read performance for the database will be greater under a Raid 5 (stripe set with parity) config. but that means combining the Logs as well. Therefore, in order to gain both performance and recovery benefits from segregating the OS, Logs and Database to their own spindle sets makes sense over a simple Raid 1 and Raid 5 config. (just as my mate Linton put it). So I'm going with three Raid 1 arrays. Cheers, _________________________________________________________________ Broadband?�Dial-up? Get reliable MSN Internet Access. http://resourcecenter.msn.com/access/plans/default.asp List info : http://www.activedir.org/mail_list.htm List FAQ : http://www.activedir.org/list_faq.htm List archive: http://www.mail-archive.com/activedir%40mail.activedir.org/ List info : http://www.activedir.org/mail_list.htm List FAQ : http://www.activedir.org/list_faq.htm List archive: http://www.mail-archive.com/activedir%40mail.activedir.org/ List info : http://www.activedir.org/mail_list.htm List FAQ : http://www.activedir.org/list_faq.htm List archive: http://www.mail-archive.com/activedir%40mail.activedir.org/
