[Users] Live storage migration snapshot removal (fails)

8 Nov 2013

      When I move a disk (of a running vm) to a different storage pool a live
snapshot ('Auto-generated for Live Storage Migration') is created.

The allocation type of the virtual disk changes from "Preallocated" to
"Thin Provision" with actual size > virtual size (e.g. 4GB actual, 1GB virtual).

This snapshot is not removed after the storage migration is completed and
cannot be removed from a running VM ( probably because live snapshot
deletion is not implemented yet?).

When I stop the VM and then remove the snapshot this fails and the snapshot
state changes to "BROKEN".

I've done some additional testing and the problem only occurs when a
preallocated
disk is used. Offline snapshot removal on a thin provisioned disk
works (no online
removal option).

Is this expected behaviour?
If so, I think live storage migration for preallocated disk should be disabled.

Attached vdsm.log of the SPM host with the DEBUG and INFO lines removed
to get it down to a manageable size.

Log excerpts:

Thread-20::WARNING::2013-11-08
13:48:30,423::persistentDict::256::Storage.PersistentDict::(refresh)
data has no embedded checksum -
trust it as it is
f686ef6c-17e7-4777-bc69-5a67d38e3fa5::WARNING::2013-11-08
13:48:44,370::lvm::594::Storage.LVM::(getLv) lv:
_remove_me_usZUyexc_9538a
a00-2b19-495e-b091-3ffa76b1543c not found in lvs vg:
9d4e8a43-4851-42ff-a684-f3d802527cf7 response
f686ef6c-17e7-4777-bc69-5a67d38e3fa5::ERROR::2013-11-08
13:48:44,375::task::850::TaskManager.Task::(_setError)
Task=`f686ef6c-17e7-4
777-bc69-5a67d38e3fa5`::Unexpected error
Traceback (most recent call last):
  File "/usr/share/vdsm/storage/task.py", line 857, in _run
    return fn(*args, **kargs)
  File "/usr/share/vdsm/storage/task.py", line 318, in run
    return self.cmd(*self.argslist, **self.argsdict)
  File "/usr/share/vdsm/storage/securable.py", line 68, in wrapper
    return f(self, *args, **kwargs)
  File "/usr/share/vdsm/storage/sp.py", line 1937, in mergeSnapshots
    sdUUID, vmUUID, imgUUID, ancestor, successor, postZero)
  File "/usr/share/vdsm/storage/image.py", line 1162, in merge
    srcVol.shrinkToOptimalSize()
  File "/usr/share/vdsm/storage/blockVolume.py", line 315, in
shrinkToOptimalSize
    volParams = self.getVolumeParams()
  File "/usr/share/vdsm/storage/volume.py", line 1008, in getVolumeParams
    volParams['imgUUID'] = self.getImage()
  File "/usr/share/vdsm/storage/blockVolume.py", line 494, in getImage
    return self.getVolumeTag(TAG_PREFIX_IMAGE)
  File "/usr/share/vdsm/storage/blockVolume.py", line 464, in getVolumeTag
    return _getVolumeTag(self.sdUUID, self.volUUID, tagPrefix)
  File "/usr/share/vdsm/storage/blockVolume.py", line 662, in _getVolumeTag
    tags = lvm.getLV(sdUUID, volUUID).tags
  File "/usr/share/vdsm/storage/lvm.py", line 851, in getLV
    raise se.LogicalVolumeDoesNotExistError("%s/%s" % (vgName, lvName))
LogicalVolumeDoesNotExistError: Logical volume does not exist:
('9d4e8a43-4851-42ff-a684-f3d802527cf7/_remove_me_usZUyexc_9538aa00-2b19-495e-b091-3ffa76b1543c',)
e5ba40e5-05a4-4e9d-9f3d-c6f2000fb296::WARNING::2013-11-08
13:49:37,921::lvm::594::Storage.LVM::(getLv) lv:
b6bae791-dc47-46c2-86e2-1557b3caa66e not found in lvs vg:
dfbbc8dd-bfae-44e1-8876-2bb82921565a response
e5ba40e5-05a4-4e9d-9f3d-c6f2000fb296::WARNING::2013-11-08
13:49:38,502::utils::113::root::(rmFile) File:
/rhev/data-center/def9b712-876a-49a9-b4b9-df9770befac4/dfbbc8dd-bfae-44e1-8876-2bb82921565a/images/c0d7b583-2f63-4c6b-9088-6f5aa84ccfcc/b6bae791-dc47-46c2-86e2-1557b3caa66e
already removed

52178458-1764-4317-b85b-71843054aae9::WARNING::2013-11-08
14:02:34,284::blockSD::742::Storage.StorageDomain::(_getOccupiedMetadataSlots)
Could not find mapping for lv
9d4e8a43-4851-42ff-a684-f3d802527cf7/c512267d-ebba-4907-a782-fec9b6c95116
52178458-1764-4317-b85b-71843054aae9::WARNING::2013-11-08
14:02:53,772::image::1164::Storage.Image::(merge) Auto shrink after
merge failed
Traceback (most recent call last):
  File "/usr/share/vdsm/storage/image.py", line 1162, in merge
    srcVol.shrinkToOptimalSize()
  File "/usr/share/vdsm/storage/blockVolume.py", line 320, in
shrinkToOptimalSize
    qemuImg.FORMAT.QCOW2)
  File "/usr/lib64/python2.6/site-packages/vdsm/qemuImg.py", line 109, in check
    raise QImgError(rc, out, err, "unable to parse qemu-img check output")
QImgError: ecode=0, stdout=['No errors were found on the image.'],
stderr=[], message=unable to parse qemu-img check output
Thread-20::ERROR::2013-11-08
14:03:42,869::sdc::137::Storage.StorageDomainCache::(_findDomain)
looking for unfetched domain 9d4e8a43-4851-42ff-a684-f3d802527cf7

[Users] Live storage migration snapshot removal (fails)

Sander Grendelman