On Jul 25, 2011, at 3:59 PM, [email protected] wrote: > Quoting Zev Weiss <[email protected]>: > >> Hi, >> >> Ken, Mark -- any further information on the write performance problem, >> and/or a solution to it? >> >> I'm running 8.3.7 at the moment, I think I'm going to try updating to 8.3.11 >> and/or 8.4 and see if it magically fixes anything (unless there are further >> suggestions on other things to try). >> >> >> Zev >> > I've put together a quick test cluster. DRBD does well on the initial disk > sync. I just went back and looked at the graphs to make sure it wasn't my > imagination. I'm beginning to think it has something to do with the > interaction of DRBD/LVM2/GFS2 that is not happy. I did most of the tweaks I > could find and it added up to 50% increase, but going from 1.5M to 2.0M isn't > exactly thrilling. > > Ken Lowther >
Yeah, I think I've seen decent performance on sync as well, but when it comes to actual usage as the backing store of a live filesystem, things go rapidly downhill -- I've been seeing about 4MB/s on my system. Not quite the 2M you're seeing, but still pretty unacceptably slow, by an order of magnitude or so. As for the source of the problem, I don't have GFS2 in the picture on my setup, so I think that'd rule out that component (assuming we're looking at the same underlying cause). I may be able to attach some extra drives to my machines and create another drbd resource to test with, so I can try e.g. with and without LVM between DRBD and the raw block devices and see if that makes a difference. Zev (I seem to have a bad habit of mistakenly replying to the sender instead of the list...sorry about that Ken.) _______________________________________________ drbd-user mailing list [email protected] http://lists.linbit.com/mailman/listinfo/drbd-user
