More about Hyper-V CSV VM Backup with CSV timeout

Article: 100026480
Last Published: 2012-03-09
Ratings: 0 0
Product(s): NetBackup

Problem

Cluster shared volumes timeout

This option applies to backups of the virtual machines that are configured in a Microsoft Cluster that uses cluster shared volumes (CSV). The timeout determines how many minutes the backup job waits, in case another node in the cluster is backing up the same shared volume.

The default is 0 (no wait). If you do not want NetBackup to wait for another backup to release the shared volume, accept the default. If another node in the cluster is backing up a shared volume that this backup requires, the backup fails with status code 156 (snapshot error encountered).

T he appropriate value for this timeout parameter depends on the following factors:

  • The average backup job duration for the virtual machines that reside on the same CSV. The duration depends on the size of the virtual machines and the I/O speed.
  • The number of virtual machines on the same CSV.

Solution

A simultaneous backup of a CSV cannot be performed from more than one node
 

When backup of a CSV is being performed from one node, an attempt to backup from another node will fail.

The CSV time out configuration parameter is the duration that a backup operation on a node will wait and keep retrying, in case simultaneous backups of the same CSV are being performed different nodes.

Example:

User-added image

In the figure above, VM1, VM2 and VM3 reside on the same CSV.

  • A backup of VM1 and VM2 can be performed simultaneously because owner node of both VMs is the same.
  • A backup of VM3 cannot be performed simultaneously with one of VM1 or VM2.
  • While a backup for VM1 and/or VM2 is in progress, a backup request for VM3 must wait and vice versa

Policy Creation: Snapshot Client Options "CSV timeout":

Policy Facelift: Hyper-V policy type

User-added image

Troubleshooting: Backup Failed with Status 156 (Failure: CSV timeout)

The bpfis log contains:
VssNode::prepareCsvsForBackup: CSV TimeOut expired, Not all required CSV available in required state

Reason: Not able to prepare all required CSV(s) for backup in specified timeout period. Backup of some required CSV is in progress from another node.

Recommended action: Increase CSV timeout period and rerun backup or try backup after some time.

 

 

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