On Thu, Dec 15, 2011 at 9:20 PM, Bill Humphries <[email protected]> wrote: > Seems everyone assumed RAID 10. Would you not consider > RAID 50 if you had 8 SAS drives and decent controller with battery backed > cache?
(Sanity check: RAID 50 = RAID 0 of RAID 5's = stripe of stripes-with-parity. You need at least three disks for RAID 5. So with 8 disks, the only configuration that uses all of them would be two 4-disk RAID 5 sets, then stripped with RAID 0. Yah?) My take is: With modern disk sizes, RAID 5 can be pretty horrible during a rebuild. Say you've got 8 x 600 GB. 4 x 600 = 2400 GB, raw. Loose one disk, replace it, and you have to read 1800 GB to rebuild that one 600 GB missing member. And with the large disk sizes, the chances of a double failure are higher, too. Sucks to find out there's a new bad block in that remaining 1800 GB. RAID 10 is nice and simple: At most you're doing I or O on an entire single disk. Plus it's much better in terms of I/O performance. Disk usage efficiency is crap at 50%, but with the low cost of storage these days, that's not as big a loss as it once was. And with only 8 disks, RAID 50 is only going to be 75% efficient, right? -- Ben ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~ --- To manage subscriptions click here: http://lyris.sunbelt-software.com/read/my_forums/ or send an email to [email protected] with the body: unsubscribe ntsysadmin
