Robert Collins wrote: >> Hand-waving aside, I >> think this explanation fits the bill. > > I dont, because you have ignored the parallelism in each spindle. > > With 10 disks, doing 10 writes, one per disk, should take precisely as > long as 5 disks, doing 5 writes, one per disk, as long as you have > bandwidth on your SCSI bus.
Yes, I'm aware of that. Unfortunately it completely blows my theory out of the water and leaves me right back where I started. To be honest, the only way I could get an accurate comparison would be to take down ServerA and rebuild it as RAID10 and see what results I get as there are simply too many other factors at play in attempting a direct comparison of the two boxes, and unfortunately at the moment there is no way I can do that. Under certain conditions ServerA was indeed slower than ServerB but on the whole the difference I saw when I changed from RAID10 to RAID5 on ServerB was significant and consistent. And like I said, the results I was seeing consistently defied anything I would have expected. Craig -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
