Bug 1119203

Update:
This bug is not depend on restarting VDSM or engine (https://bugzilla.redhat.com/show_bug.cgi?id=1119236).

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Description of problem:
Creation of live snapshot ends with failure message from engine side that:
"Failed to complete snapshot 'snapshot_343074' creation for VM 'vm_0'."

The snapshot is actually created successfully and all relevant volumes are exists.

** Closing bug: https://bugzilla.redhat.com/show_bug.cgi?id=1119236


Version-Release number of selected component (if applicable):
ovirt-engine-3.5.0-0.0.master.20140629172257.git0b16ed7.el6.noarch
vdsm-4.16.0-3.git601f786.el6.x86_64


How reproducible:
100%

Steps to Reproduce:
1. Start a live snapshot operation
2. restart VDSM
3.

Actual results:
The snapshot is created and all the volumes exists and the failure message is shown.

Expected results:
the snapshot should succeeded with no Failure message OR the snapshot creation should fail with failure message

I don't understand the difference between this one and bug 1119236.
Raz, can you please clarify?

This bug is about normal live snapshot creation that ends with the above error message. bug 1119236 is about restarting the engine during a live snapshot.
The reason I opened it is because I thought that the engine restart is the problem but then I performed a live snapshot with no engine restart and figured that the problem is not the engine restart.

According to the logs, it seems like another duplicate of bug 870928 and bug 1064419. The failure has occurred during the live snapshot operation. In which, according to the design, an event log is displayed [1] (and an error log [2]); but no rollback is done on the snapshot (as it's still usable). See bug 870928 - comment #4.

[1] Message: Failed to create live snapshot 'snapshot_343074' for VM 'vm_0'. VM restart is recommended.

[2] VDSErrorException: Failed to SnapshotVDS, error = Snapshot failed, code = 48 (Failed with error SNAPSHOT_FAILED and code 48). VM will still be configured to the new created snapshot

*** This bug has been marked as a duplicate of bug 870928 ***

The snapshot is not usable after this scenario - bug 1119691
Reopening the bug

(In reply to ratamir from comment #6)
> The snapshot is not usable after this scenario - bug 1119691
> Reopening the bug

Hi Raz,

What do you mean by 'not usable'? Snapshot volumes have been created?
What is the scenario? restart vdsm during live snapshot?

Hi Daniel,
Sorry for the not so clear bug and changing the reason.
The bug is that when creating a live snapshot, the engine report that:
"Failed to complete snapshot 'snapshot_343074' creation for VM 'vm_0'."
Restarting vdsm is out of the scope of this bug. I thought that the reason is the vdsm restart but Live snapshot "fails" even without the vdsm restart.
You mentioned in comment 4 that "...no rollback is done on the snapshot (as it's still usable).", so I checked this and the snapshot is not usable (as described in bug 1119691).
And the snapshot volume created.

On failure of live snapshot, using the newly created snapshot might lead to data inconsistency (similar to bug 870928). As roll-back is not applicable in such scenario (the created snapshot could be deleted when the VM is down), we might want to add/replace the warning with an error audit log to explicitly state that using the created snapshot might cause data inconsistency. Thoughts?

Verified - The live snapshot created successfully

oVirt 3.5 has been released and should include the fix for this issue.