On Fri, Dec 12, 2003 at 08:19:19PM +1000, Peter Kiem wrote: > For this new server I am purchasing however I decided to get a 3ware > 7506-4LP raid card and 4x80GB drives. The server will do general things > like email, web, ftp, dns, etc and will be running RHEL. > > With 4 drives, I can either do raid-5 with a hotspare or raid-10. Both > will give me 160GB of space and theoretically can withstand the loss of > 2 drives. It depends on your workload mix. For a read operation on RAID-5, you're splitting your reads across 3 spindles. For RAID-10 (which isn't really RAID-10, but RAID 1+0), each read will be serviced by only 2 spindles. So, for reads, RAID-5 is better. However, for writes, RAID 1+0 really wins since there are no RAID 5 calculations to do. In a heavy write situation, I'd definitely chose RAID 1+0. Given the mix you specified, I'd go with RAID-5. I've said it here before, but I'll say it again. I have seen 2 disks die in a RAID-5 set - and those failures happened close together. The first time, I lost a member on a Friday night after I'd gone home, the hot spare kicked in and rebuilt the set, and then Sunday night I lost another member of the same raidset. I was saved by the hot spare. The second time (different raidset) I lost the drive, and while it was rebuilding the raidset, another drive died. End of raid set - restore time. Thankfully in that case, the raidset was software mirrored to another data center and the users did not lose access to the data - the recovery was totally transparent to the users. -- Ed Wilts, Mounds View, MN, USA mailto:ewilts@xxxxxxxxxx Member #1, Red Hat Community Ambassador Program -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list
