On Mon, 15 Feb 2016 17:04:55 +0000, freebird wrote: > On Mon, 15 Feb 2016 15:29:39 +0100, Lars Ellenberg wrote: > > On Fri, Feb 12, 2016 at 04:10:14PM +0000, freebird wrote: > > > Hi, I have a memory usage problem with the resync sender on a single > > > resource. If the total size of the out of sync blocks exceeds the > > > memory size when drbd connects, the sync progresses until it exhausts > > > the memory leading to the OOM killer kicking in (too slowly to make > > > any difference) followed by a kernel panic. Everything else including > > > replication of very large files that exceed the memory size, works > > > fine. > > > > > > I've tested with out of sync sizes up to just short of the total > > > memory when the resync succeeds and observed that the memory used > > > increases in line with sync'ed blocks i.e. the resync process seems to > > > be allocating memory per block and doesn't release or reuse it ... > > > only when the resync completes does the memory get released. The > > > strange thing is that I can't find which specific process is retaining > > > the memory ... nothing shows up in top, slabtop or the process table. > > > > We regularly resync terrabytes of dummy data in test VMs that have > > only a few hundred megs of ram allocated. So I seriously doubt > > that this was a generic DRBD issue, but would suggest that > > something is off in your deployment. > > > Hi Lars, that's what I suspected myself as I know the DRBD user base is large > and googling didn't find anyone else with the issue but I was just hoping for > some suggestions. Anyway, it turns out to be an XFS issue ... if I dismount > the filesystem before the resync, the problem doesn't occur. The XFS setup > hasn't been tweaked from what mkfs.xfs defaults created so I'll investigate > tuning or even using a different filesystem. Thanks for the reply, Nige. > Hi Lars, ignore comments about XFS. It was a duff test and it makes no difference whether a filesystem is mounted or not (you just can't get the staff these days:). Will try DRBD 83 on current build and also 84 on a kernel v3 distro. Nige.
-- Unix never says 'please'. [Rob Pike] _______________________________________________ drbd-user mailing list [email protected] http://lists.linbit.com/mailman/listinfo/drbd-user
