On Thu, 20 Oct 2005 at 9:43am, Aleksandar Milivojevic wrote > Quoting Joshua Baker-LePain <jlb17 at duke.edu>: > >> Needless to say it's not giving me that warm fuzzy feeling. The one caveat >> is that not all the members of my array were the same size -- one disk is >> 180GB while all the rest are 160GB. I'm going to test overnight with >> identically sized RAID members, but I also wanted to see if anyone else is >> using RAID6. > > I was testing RAID-5 with identical disk drives. Got the same thing. If I > attempt to access it while it rebuilds, sooner or later I get errors. If I > reboot while it rebuilds, it doesn't start it after the reboot (forgot the > actuall error message). I needed to manually kick it again using mdadm to > force-start it. If it was root file system, the machine would probably fail > to > boot completely. You might want to stick to your 3ware for now. Wonderful. I'm testing RAID5 now, for which I had high hopes. > BTW, any particular reason not to use hardware RAID on 3ware? That was the initial plan. But I can't get anything even resembling decent speeds out of them. These systems have 2 7500-8 boards in 'em (on separate PCI buses). I had been running RH7.3 (!!) and XFS with the boards in hardware RAID5 and a software RAID0 stripe across those, and would get >100MB/s writes and >300MB/s reads. With centos-4 and ext3, I was getting ~30MB/s writes and ~200MB/s reads. The reads I'd be OK with, but the write speed is absurd. I tweaked all I could think of, but nothing helped much. -- Joshua Baker-LePain Department of Biomedical Engineering Duke University