+Krutika Dhananjay and gluster ml On Tue, Mar 26, 2019 at 6:16 PM Sander Hoentjen <sander(a)hoentjen.eu&gt; wrote: > Hello, > > tl;dr We have disk corruption when doing live storage migration on oVirt > 4.2 with gluster 3.12.15. Any idea why? > > We have a 3-node oVirt cluster that is both compute and gluster-storage. > The manager runs on separate hardware. We are running out of space on > this volume, so we added another Gluster volume that is bigger, put a > storage domain on it and then we migrated VM's to it with LSM. After > some time, we noticed that (some of) the migrated VM's had corrupted > filesystems. After moving everything back with export-import to the old > domain where possible, and recovering from backups where needed we set > off to investigate this issue. > > We are now at the point where we can reproduce this issue within a day. > What we have found so far: > 1) The corruption occurs at the very end of the replication step, most > probably between START and FINISH of diskReplicateFinish, before the > START merge step > 2) In the corrupted VM, at some place where data should be, this data is > replaced by zero's. This can be file-contents or a directory-structure > or whatever. > 3) The source gluster volume has different settings then the destination > (Mostly because the defaults were different at creation time): > > Setting old(src) new(dst) > cluster.op-version 30800 30800 (the same) > cluster.max-op-version 31202 31202 (the same) > cluster.metadata-self-heal off on > cluster.data-self-heal off on > cluster.entry-self-heal off on > performance.low-prio-threads 16 32 > performance.strict-o-direct off on > network.ping-timeout 42 30 > network.remote-dio enable off > transport.address-family - inet > performance.stat-prefetch off on > features.shard-block-size 512MB 64MB > cluster.shd-max-threads 1 8 > cluster.shd-wait-qlength 1024 10000 > cluster.locking-scheme full granular > cluster.granular-entry-heal no enable > > 4) To test, we migrate some VM's back and forth. The corruption does not > occur every time. To this point it only occurs from old to new, but we > don't have enough data-points to be sure about that. > > Anybody an idea what is causing the corruption? Is this the best list to > ask, or should I ask on a Gluster list? I am not sure if this is oVirt > specific or Gluster specific though. Do you have logs from old and new gluster volumes? Any errors in the new volume's fuse mount logs?

Could you enable strict-o-direct and disable remote-dio on the src volume as well, restart the vms on "old" and retry migration? # gluster volume set <VOLNAME> performance.strict-o-direct on # gluster volume set <VOLNAME> network.remote-dio off -Krutika On Tue, Mar 26, 2019 at 10:32 PM Sander Hoentjen <sander(a)hoentjen.eu&gt; wrote: > On 26-03-19 14:23, Sahina Bose wrote: > > +Krutika Dhananjay and gluster ml > > > > On Tue, Mar 26, 2019 at 6:16 PM Sander Hoentjen <sander(a)hoentjen.eu&gt; > wrote: > >> Hello, > >> > >> tl;dr We have disk corruption when doing live storage migration on > oVirt > >> 4.2 with gluster 3.12.15. Any idea why? > >> > >> We have a 3-node oVirt cluster that is both compute and > gluster-storage. > >> The manager runs on separate hardware. We are running out of space on > >> this volume, so we added another Gluster volume that is bigger, put a > >> storage domain on it and then we migrated VM's to it with LSM. After > >> some time, we noticed that (some of) the migrated VM's had corrupted > >> filesystems. After moving everything back with export-import to the old > >> domain where possible, and recovering from backups where needed we set > >> off to investigate this issue. > >> > >> We are now at the point where we can reproduce this issue within a day. > >> What we have found so far: > >> 1) The corruption occurs at the very end of the replication step, most > >> probably between START and FINISH of diskReplicateFinish, before the > >> START merge step > >> 2) In the corrupted VM, at some place where data should be, this data > is > >> replaced by zero's. This can be file-contents or a directory-structure > >> or whatever. > >> 3) The source gluster volume has different settings then the > destination > >> (Mostly because the defaults were different at creation time): > >> > >> Setting old(src) new(dst) > >> cluster.op-version 30800 30800 (the same) > >> cluster.max-op-version 31202 31202 (the same) > >> cluster.metadata-self-heal off on > >> cluster.data-self-heal off on > >> cluster.entry-self-heal off on > >> performance.low-prio-threads 16 32 > >> performance.strict-o-direct off on > >> network.ping-timeout 42 30 > >> network.remote-dio enable off > >> transport.address-family - inet > >> performance.stat-prefetch off on > >> features.shard-block-size 512MB 64MB > >> cluster.shd-max-threads 1 8 > >> cluster.shd-wait-qlength 1024 10000 > >> cluster.locking-scheme full granular > >> cluster.granular-entry-heal no enable > >> > >> 4) To test, we migrate some VM's back and forth. The corruption does > not > >> occur every time. To this point it only occurs from old to new, but we > >> don't have enough data-points to be sure about that. > >> > >> Anybody an idea what is causing the corruption? Is this the best list > to > >> ask, or should I ask on a Gluster list? I am not sure if this is oVirt > >> specific or Gluster specific though. > > Do you have logs from old and new gluster volumes? Any errors in the > > new volume's fuse mount logs? > > Around the time of corruption I see the message: > The message "I [MSGID: 133017] [shard.c:4941:shard_seek] > 0-ZoneA_Gluster1-shard: seek called on > 7fabc273-3d8a-4a49-8906-b8ccbea4a49f. [Operation not supported]" repeated > 231 times between [2019-03-26 13:14:22.297333] and [2019-03-26 > 13:15:42.912170] > > I also see this message at other times, when I don't see the corruption > occur, though. > > -- > Sander > _______________________________________________ > Users mailing list -- users(a)ovirt.org > To unsubscribe send an email to users-leave(a)ovirt.org > Privacy Statement: https://www.ovirt.org/site/privacy-policy/ > oVirt Code of Conduct: > https://www.ovirt.org/community/about/community-guidelines/ > List Archives: > https://lists.ovirt.org/archives/list/users@ovirt.org/message/M3T2VGGGV6D... > _______________________________________________ Users mailing list -- users(a)ovirt.org To unsubscribe send an email to users-leave(a)ovirt.org Privacy Statement: https://www.ovirt.org/site/privacy-policy/ oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/ZUIRM5PT4Y4...

This is needed to prevent any inconsistencies stemming from buffered writes/caching file data during live VM migration. Besides, for Gluster to truly honor direct-io behavior in qemu's 'cache=none' mode (which is what oVirt uses), one needs to turn on performance.strict-o-direct and disable remote-dio. -Krutika On Wed, Mar 27, 2019 at 12:24 PM Leo David <leoalex(a)gmail.com <mailto:leoalex@gmail.com>> wrote: Hi, I can confirm that after setting these two options, I haven't encountered disk corruptions anymore. The downside, is that at least for me it had a pretty big impact on performance. The iops really went down - performing  inside vm fio tests. On Wed, Mar 27, 2019, 07:03 Krutika Dhananjay <kdhananj(a)redhat.com <mailto:kdhananj@redhat.com>> wrote: Could you enable strict-o-direct and disable remote-dio on the src volume as well, restart the vms on "old" and retry migration? # gluster volume set <VOLNAME> performance.strict-o-direct on # gluster volume set <VOLNAME> network.remote-dio off -Krutika On Tue, Mar 26, 2019 at 10:32 PM Sander Hoentjen <sander(a)hoentjen.eu <mailto:sander@hoentjen.eu>> wrote: On 26-03-19 14:23, Sahina Bose wrote: > +Krutika Dhananjay and gluster ml > > On Tue, Mar 26, 2019 at 6:16 PM Sander Hoentjen <sander(a)hoentjen.eu <mailto:sander@hoentjen.eu>> wrote: >> Hello, >> >> tl;dr We have disk corruption when doing live storage migration on oVirt >> 4.2 with gluster 3.12.15. Any idea why? >> >> We have a 3-node oVirt cluster that is both compute and gluster-storage. >> The manager runs on separate hardware. We are running out of space on >> this volume, so we added another Gluster volume that is bigger, put a >> storage domain on it and then we migrated VM's to it with LSM. After >> some time, we noticed that (some of) the migrated VM's had corrupted >> filesystems. After moving everything back with export-import to the old >> domain where possible, and recovering from backups where needed we set >> off to investigate this issue. >> >> We are now at the point where we can reproduce this issue within a day. >> What we have found so far: >> 1) The corruption occurs at the very end of the replication step, most >> probably between START and FINISH of diskReplicateFinish, before the >> START merge step >> 2) In the corrupted VM, at some place where data should be, this data is >> replaced by zero's. This can be file-contents or a directory-structure >> or whatever. >> 3) The source gluster volume has different settings then the destination >> (Mostly because the defaults were different at creation time): >> >> Setting                                 old(src)  new(dst) >> cluster.op-version                      30800     30800 (the same) >> cluster.max-op-version                  31202     31202 (the same) >> cluster.metadata-self-heal              off       on >> cluster.data-self-heal                  off       on >> cluster.entry-self-heal                 off       on >> performance.low-prio-threads            16        32 >> performance.strict-o-direct             off       on >> network.ping-timeout                    42        30 >> network.remote-dio                      enable    off >> transport.address-family                -         inet >> performance.stat-prefetch               off       on >> features.shard-block-size               512MB     64MB >> cluster.shd-max-threads                 1         8 >> cluster.shd-wait-qlength                1024      10000 >> cluster.locking-scheme                  full      granular >> cluster.granular-entry-heal             no        enable >> >> 4) To test, we migrate some VM's back and forth. The corruption does not >> occur every time. To this point it only occurs from old to new, but we >> don't have enough data-points to be sure about that. >> >> Anybody an idea what is causing the corruption? Is this the best list to >> ask, or should I ask on a Gluster list? I am not sure if this is oVirt >> specific or Gluster specific though. > Do you have logs from old and new gluster volumes? Any errors in the > new volume's fuse mount logs? Around the time of corruption I see the message: The message "I [MSGID: 133017] [shard.c:4941:shard_seek] 0-ZoneA_Gluster1-shard: seek called on 7fabc273-3d8a-4a49-8906-b8ccbea4a49f. [Operation not supported]" repeated 231 times between [2019-03-26 13:14:22.297333] and [2019-03-26 13:15:42.912170] I also see this message at other times, when I don't see the corruption occur, though. -- Sander _______________________________________________ Users mailing list -- users(a)ovirt.org <mailto:users@ovirt.org> To unsubscribe send an email to users-leave(a)ovirt.org <mailto:users-leave@ovirt.org> Privacy Statement: https://www.ovirt.org/site/privacy-policy/ oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/M3T2VGGGV6D... _______________________________________________ Users mailing list -- users(a)ovirt.org <mailto:users@ovirt.org> To unsubscribe send an email to users-leave(a)ovirt.org <mailto:users-leave@ovirt.org> Privacy Statement: https://www.ovirt.org/site/privacy-policy/ oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/ZUIRM5PT4Y4... _______________________________________________ Gluster-users mailing list Gluster-users(a)gluster.org https://lists.gluster.org/mailman/listinfo/gluster-users