Our CommVault instance uses Nimble storage for data backup. When CommVault tries to backup VM, it tells vCenter to take a snapshot of this VM. After snapshot is created by vCenter, CommVault backup it.
At the same time we have Nimble replication process. When Nimble discovers a new snapshot (created by CommVault), it puts the snapshot in the queue for the replication.
When CommVault finishes backup, it tells vCenter to delete snapshot. But if the replication of the snapshot was not finished, Nimble replication process prevents snapshot being deleted. At the same time vCenter does not generate any failure for the CommVault.
At the very end:
- CommVault does not repeat an attempt to delete because it does not know that this attempt failed (I tried to decrease nExpireSnapshotHours parameter value, but this do not help; other snapshot-related parameters are not applicable because no failures nor error are generated);
- vCenter seems to lose the control/ownership on this snapshot and does left this snapshot as "being online";
- Nimble does not delete "a foreign" snapshot too.
And the count of snapshot becomes invincible - till it becomes greater than the maximum count that Nimble allows to maintain.
The question is:
- does CommVault have a special parameter that allow to increase the interval between the end of backup time and the time when CommVault asks vCenter to delete the snapshot?
I've checked CommVault Additional settings, but found no parameter that defines such interval.
Summary:
1.) CommVault asks vCenter to take a snapshot of the VM,
2.) Nimble array discovers the snapshot and puts in the queue for replication
3.) CommVault finishes and asks vCenter to delete the snapshot
4.) If the Nimble array has not finished replicating the snapshot, it refuses to delete it.
5.) vCenter on its side is also done with it and doesn’t feel ownership anymore.
6.) The Nimble array finishes the replication and leaves the snapshot alone since it was triggered outside of the array
7.) Since the state was online, the snapshot remains online.