If it's all one disk group, then performance will be at the least common denominator of the various virtual disk architectures at best.
So, do you care? I dunno. RAID5 runs about 4x slower than RAID1 on writes in many cases, so unless there are 4x spindles available in the disk group, you're worse off without even looking at the application. Exchange log performance is optimized by having dedicated spindles that don't have to re-seek for every write. So beyond the difference in RAID level write performance, you have an application level difference. If they're saying that the EVA will give you the same number of I/O's for both the logs and the databases as you would have seen for just the logs on a standalone set of spindles, then go for it. What's not stated is what your performance needs are. What I/O rate will the EVA deliver to the log volume on a sustainable basis? Is that enough to support your user load? Any other question is just an academic exercise. ======================================================= Andy Webb [EMAIL PROTECTED] www.swinc.com Simpler-Webb, Inc. Austin, TX 512-322-0071 ======================================================= -----Original Message----- From: Rosenthal, Daniel A. [mailto:[EMAIL PROTECTED]] Posted At: Monday, August 26, 2002 8:11 AM Posted To: Microsoft Exchange Conversation: HP/Compaq EVA Subject: RE: HP/Compaq EVA As I understand it we will have exclusive access to a disk group; the other disk group in the EVA will be used for other apps. With that assumption do we care about the differences between vraid1 and vraid5 when all the physical volumes will be within this disk group? As I understand it, splitting this group into 2 or more will reduce the number of spindles, reduce the EVA-based fault protection and reduce the overall performance. Daniel Rosenthal National Grid USA Messaging Support (508)389-2625 -----Original Message----- From: Ed Crowley [mailto:[EMAIL PROTECTED]] Sent: Sunday, August 25, 2002 12:13 PM To: Exchange Discussions Subject: RE: HP/Compaq EVA Just so happens that I've been in an internal discussion about this and that's what I'm being told myself. I don't disagree with the principles at all. However, your performance really will be dependent upon your application mix and how you map them to the virtual arrays. Ed Crowley MCSE+Internet MVP kcCC+I Tech Consultant hp Services Protecting the world from PSTs and Bricked Backups! -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Rosenthal, Daniel A. Sent: Sunday, August 25, 2002 6:59 AM To: Exchange Discussions Subject: HP/Compaq EVA Does anyone have any experiences with HP/Compaq's Enterprise Virtual Array in regards to Exchange 2000? They'd like us to believe, it seems, that the rules about transaction logs and databases being on seperate physical volumes do not apply using this technology, because fault tolerance is spread across so many volumes in the disk group. Also they would have us believe that with vraid5 for both logs and databases we'd see no performance issues. The big stress is that this isn't your older brother's scsii raid anymore. Thanks. This e-mail and any files transmitted with it, are confidential to National Grid and are intended solely for the use of the individual or entity to whom they are addressed. If you have received this e-mail in error, please contact the National Grid USA Help desk on 508-389-3375. _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe: mailto:[EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe: mailto:[EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe: mailto:[EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Archives: http://www.swynk.com/sitesearch/search.asp To unsubscribe: mailto:[EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED]
