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Virtual machines residing on NFS storage become unresponsive during a snapshot removal operation (2010953)

Symptoms

When using NFSv3 to mount NFS datastores, and a VADP-enabled backup solution, such as VMware Data Recovery, that uses the hot-add method, you experience these symptoms:
  • During a snapshot removal operation, virtual machines residing on NFS storage become unresponsive.
  • When removing snapshots after backing up a virtual machine residing on an NFS datastore using a backup application, the virtual machine becomes unresponsive for approximately 30 seconds.
  • Removing snapshots after backing up a virtual machine residing on an NFS datastore takes a long time to complete.
  • This issue occurs when the target virtual machine disk was hot-added for the backup/restore operation.

Cause

This is a known issue which occurs when the target virtual machine and the backup appliance reside on two different hosts, and the NFSv3 protocol is used to mount NFS datastores. A limitation in the NFSv3 locking method causes a lock timeout, which pauses the virtual machine being backed up.

Resolution

This issue is resolved by using the NFSv4 protocol for mounting NFS volumes.

Note: NFSv4 is released with ESXi 6.0, and later versions. It is not available in earlier versions.

To work around this issue, ensure that the virtual machine resides in the same host where the backup appliance is installed.

Note
: Alternatively, you can use LAN/NBD transport that uses the NFC (Network File Copy) in your backup solution or disable SCSI hot-add through the backup software. For more information about NBD transport, see the Virtual Disk Transport Methods section in the Virtual Disk Programming guide.

Additional Information

For more information on virtual machine losing connection during snapshot removal, see VM Loses Connection During Snapshot Removal.

Note: The preceding link was correct as of November 10, 2014. If you find the link is broken, provide feedback and a VMware employee will update the link.  

Tags

nfs unresponsive 30 seconds,nfs snapshot

See Also

This Article Replaces

2033540

Update History

08/29/2012 - Updated Product Versions to include ESXi 5.0.x 12/12/2012 - Updated Product Versions to include ESXi 5.1.x

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