--- Bill Davidsen <davidsen@xxxxxxx> wrote: > Andargor The Wise wrote: > > >Yet another thing, someone has suggested that I > should > >increase the chunk size for my RAID5 from 32 to > either > >64 or 128. > > > >Is it worth it, considering that the system doesn't > >normally run on a heavy load? Mail for a few users, > >some read-only database applications, website, etc. > >Mostly a development machine. > > > > > Can't think of a case where it's not worth having > better performance... > I should write a WP on stripe size, and what happens > as you change it > with given loads. > If anyone's interested, I ran some benchmarks: http://www.andargor.com/raid5.html I'll be spending the time to go to 128k chunks. :) I was considering raidreconf, and tested it on a scratch partition. It worked ok, but it was slow (1.17 MB/sec overall). I'll rsync or find -xdev | cpio -admpv instead to mirror the existing stuff elsewhere before blowing away the array. > >Would this alleviate the "pauses" during large file > >transfers/copies that I have indicated in my > previous > >post? > > > >I'm asking because backing up ~176 GB, > reconfiguring > >the RAID, and restoring it properly so the machine > >boots (the RAID5 is /) is quite a PITA. > > > > You may have some special case, but I would never > put data that large in > / just as a system admin issue. It makes backups and > restores, as well > as upgrades quite unpleasant. I guess you may have > noticed that by now > ;-) Good luck! Concerning the "pause" issue, I believe my problem was not really a problem at all. The priority isn't on intreactive traffic (CONFIG_PREEMPT=n), so it was just a perception of a pause during "ls". If I had real "pauses" in my IO, I would have seen dismal benchmark results. Since I'll be recreating the array anyway, I might as well split /, /home, and /var into three RAID5's. Andargor __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
