FWIW, everything is IO bound, as Martin mentioned. From Wikipedia: http://en.wikipedia.org/wiki/IOPS
7200RPM SATA drives - ~90 IOPS 10kRPM Serial Attached SCSI drives - ~ 140 IOPS 15kRPM Serial Attached SCSI drives - ~180 IOPS For the sake of comparison, I also have some data on Fiber Channel drives from one of my contacts @ EMC - sequential IOPS for 10Kk RPM FC drive is about 300 IOPS, while random IOPS would be about 260. for a 15k RPM FC drive that jumps by about 100 IOPS (for random - probably about the same jump for sequential, but not entirely sure). Move from FC to SSD and that jumps to 5000 IOPS! Notice the IOP rating for the Violin Memory Appliance - INSANE! Another good resource for understanding RAID and how IO impacts RAID performance: http://www.acnc.com/raid.html Jonathan L. Raper, A+, MCSA, MCSE Technology Coordinator Eagle Physicians & Associates, PA [email protected] www.eaglemds.com -----Original Message----- From: Terry Dickson [mailto:[email protected]] Sent: Wednesday, June 24, 2009 11:02 AM To: NT System Admin Issues Subject: RE: HDD spindle speed RAID I have had a drive fail from Dell, it was a 10K drive. For a replacement they sent me a 15K drive and everything ran just fine. But I agree with the rest I think it will really depend on the controller, and you will be at the mercy of the slowest drive. -----Original Message----- From: Steven M. Caesare [mailto:[email protected]] Sent: Wednesday, June 24, 2009 9:58 AM To: NT System Admin Issues Subject: RE: HDD spindle speed RAID Shouldn't need to match... you'll be hamstrung by the slower drive, however. -sc From: David Lum [mailto:[email protected]] Sent: Wednesday, June 24, 2009 10:46 AM To: NT System Admin Issues Subject: HDD spindle speed RAID Does matching HDD spindle speed matter when you are RAID-ing arrays? Can you have RAID 1 with a 10,000rpm drive and a 7200RPM one? The controller just adjusts when it's waiting to know both drives are ready for more data, right? Somehow I seem to think they need to match - is it only specific conditions? Hardware raid vs software perhaps? Only stuff other than RAID 0 or 1? Or was the crack I smoked still having an effect? Bueller? David Lum // SYSTEMS ENGINEER NORTHWEST EVALUATION ASSOCIATION (Desk) 971.222.1025 // (Cell) 503.267.9764 ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ Any medical information contained in this electronic message is CONFIDENTIAL and privileged. It is unlawful for unauthorized persons to view, copy, disclose, or disseminate CONFIDENTIAL information. This electronic message may contain information that is confidential and/or legally privileged. It is intended only for the use of the individual(s) and/or entity named as recipients in the message. If you are not an intended recipient of this message, please notify the sender immediately and delete this material from your computer. Do not deliver, distribute or copy this message, and do not disclose its contents or take any action in reliance on the information that it contains. ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
