SnapProtect - NetApp - Troubleshooting

Snap creation fails with a busy LUN error

Symptom

Snapshot enters a busy state.

Cause

Busy snapshots may cause SnapProtect backups to go into a pending state.

Snapshots enter a busy state when one of the following situations occurs:

  • When a new snap is created while the backup copy operation is running. The snap may remain busy until the dependent snap is deleted.
  • When snapshots are mounted manually outside of the SnapProtect backup, through the CommCell Console, or for SnapProtectbackup operations, such as backup copy creation.

Resolution

To resolve this issue, delete the busy snapshot:

  1. Delete, in reverse order, any snaps created when LUNs were mounted out of this snapshot
  2. Unmount any LUNs mounted out of the snapshot.
  3. If the busy snapshot is no longer mounted but still shows as busy, delete all other snaps that were created while the busy snap was mounted.

To avoid future SnapProtect backup failures due to busy snapshots, follow these guidelines:

Do not run an SnapProtect backup operation on a volume that has mounted LUNs.

The SnapProtect backup software detects busy snapshots and prevents you from creating an additional snapshot until there are no busy snaps. To avoid this snapshot dependency, do not manually create a snapshot of a volume while you have a snapshot mounted.

To avoid the snap dependency on NetApp ONTAP version 7.3 and later, set the snapshot_clone_dependency or snapshot-clone-dependency volume option to on, on 7-Mode or Cluster-Mode, respectively. With this option turned on, the snapshots can be deleted in any order even if they contain LUN clones.

If you are using any application which relies on clones of LUNs on the same volume, review the NetApp documentation for impacts caused by using the snapshot_clone_dependency volume option. Refer to the article Examples of deleting backing Snapshot copies of deleted LUN clones, on the NetApp library.

If you need to restore a usable LUN clone from a snapshot, the complete sequence of snapshots containing the clone, from the snapshot used to create the LUN clone up to the restore might need to be present on the volume.

Valid snapshots might get deleted before the snap backup jobs gets aged

If the option Automatically delete older Snapshot copies is checked on the volume properties on the NetApp console, valid snapshots might get deleted from the NetApp volume before the snap backup job gets aged in SnapProtect , which is a data loss scenario. To avoid the problem:

  • Clear the Automatically delete older Snapshot copies checkbox
  • Ensure that you monitor the volume space usage and number of snaps on the NetApp console.

You can also use a command line to enable or disable Automatically delete older Snapshot copies:

snap autodelete vol_name <on | off>

where vol_name is the name of the volume.

Unable to List Rules for Export for NetApp Cluster-Mode Mounts

Symptom

When you try to mount an NFS export through the NetApp Cluster-Mode, the following error is displayed:

Unable to list rules for export

Resolution

For NetApp Cluster-Mode, if an application mounts a directory or qtree in a volume, you must explicitly specify that the NFS export is created on the volume and the directory or the qtree is mounted. You can do this by defining the value for the additional setting sMOAllowCmodeNFSFolderMountSnap to Y (or y).

Complete the following steps to set the sMOAllowCmodeNFSFolderMountSnap additional setting:

  1. From the CommCell Browser, expand to Client Computers.
  2. Right-click the client computer , then click Properties.
  3. In the Client Computer Properties dialog box, click Properties.
  4. In the Advanced Client Properties dialog box, click the Additional Settings tab and click Add .
  5. In the Add Additional Settings dialog box, specify the following:
    1. In the Name box, type sMOAllowCmodeNFSFolderMountSnap.
    2. In the Value box, type Y or y, and click OK.
    3. The Category and Type details will be automatically populated.
  6. Click OK to close Advanced Client Properties dialog box.
  7. Click OK to close Client Computer Properties dialog box.