----- "Grant McWilliams" grantmasterflash@gmail.com wrote:
On Wed, Dec 2, 2009 at 9:48 PM, Christopher G. Stach II < cgs@ldsys.net > wrote:
----- "Grant McWilliams" < grantmasterflash@gmail.com > wrote:
a RAID 10 (or 0+1) will never reach the write... performance of a RAID-5.
(*cough* If you keep the number of disks constant or the amount of usable space? "Things working" tends to trump CapEx, despite the associated pain, so I will go with "amount of usable space.")
No.
-- Christopher G. Stach II
Nice quality reading. I like theories as much as the next person but I'm wondering if the Toms Hardware guys are on crack or you disapprove of their testing methods.
http://www.tomshardware.com/reviews/external-raid-storage,1922-9.html
They used a constant number of disks to compare two different hardware implementations, not to compare RAID 5 vs. RAID 10. They got the expected ~50% improvement from the extra stripe segment in RAID 5 with a serial access pattern. Unfortunately, that's neither real world use nor the typical way you would fulfill requirements. If you read ahead to the following pages, you have a nice comparison of random access patterns and RAID 10 coming out ahead (with one less stripe segment and a lot less risk):
http://www.tomshardware.com/reviews/external-raid-storage,1922-11.html http://www.tomshardware.com/reviews/external-raid-storage,1922-12.html