On Sun, Dec 04, 2016 at 05:14:51PM -0800, Cyril Peponnet wrote: > > > On Dec 4, 2016, at 3:50 PM, Dave Chinner <david@xxxxxxxxxxxxx> > > wrote: > > > > On Sun, Dec 04, 2016 at 03:24:50PM -0800, Cyril Peponnet wrote: > >>> On Dec 4, 2016, at 2:46 PM, Dave Chinner <david@xxxxxxxxxxxxx> > >>> Which used LVM snapshots to take snapshots of the entire > >>> brick. I don't see any LVM in your config, so I'm not sure > >>> what snapshot implementation you are using here. What are you > >>> using to take the snapshots of your VM image files? Are you > >>> actually using the qemu qcow2 snapshot functionality rather > >>> than anything native to gluster? > >>> > >> > >> Yes sorry it was not clear enough, qemu-img snapshots no native > >> snapshots. > > > > Ok, so that's a fragmentation problem in it's own right. both > > internal qcow2 fragmentation and file fragmentation. > > > >>> Also, can you attach the 'xfs_bmap -vp' output of some of > >>> these image files and their snapshots? > >> > >> A snapshot: > >> https://gist.github.com/CyrilPeponnet/8108c74b9e8fd1d9edbf239b2872378d > >> (let me know if you need more basically there is around 600 > >> live snapshots sitting here). > > > > 1200 extents, mostly small, almost entirely adjacent. Typical > > qcow2 file fragmentation pattern. That's not going to cause your > > memory allocation problems - can you find one that has hundreds > > of thousands of extents? > > I found one with 10799109 :/ 576GB in size (I need to find why > this one is so big this is not normal…)… Could it lead to > the issue? The memory allocation issue, yes. 10 million extents is unusually high even for VM image files... > I mean could one file cause the deadlock of the entire > FS? What deadlock is that? XFS is reporting memory allocation issues, not that there is a filesystem deadlock. Your comments that dropping caches make the problem go away indicate that there isn't any deadlock, just blocking on memory allocation that is taking a long time to resolve... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
