Storage Node Affinity

The link between a client resource and a list of storage nodes is called storage node affinity. You define storage node affinity in the Storage Nodes attribute in the Clients resource. The default setting for the Storage Nodes attribute on most Backup client resources is the Backup server. For the client resource of a storage node machine, the default setting of the Storage Nodes attribute is the storage node and the Backup server. You can add the names of other storage nodes to the list. The Backup server uses the list in the Storage Nodes attribute to determine which device writes the data from each savestream.

When the server's index and the bootstrap save set are backed up, the data is always written to a device that is local to the Backup server. A bootstrap cannot be backed up to a remote device, but a bootstrap clone can be written to a remote device. If you use mmrecov to recover a bootstrap save set or the server's index, you must recover the data from a local device.

During backup, only the devices attached to the storage node machine in the Storage Nodes attribute list are considered to receive that client's data. You cannot specify a different list of storage nodes to be used for different operations, but you can add and remove storage node names from the Storage Nodes attribute in the Clients resource at any time.

If a backup fails with the following message, the problem is storage node affinity:

no matching devices; check storage nodes, devices or pools

Common storage node affinity problems include the following:

• No devices are enabled on the storage nodes in the Storage Nodes list.

• The devices do not have volumes that match the pool required by a backup request.

• All devices are set to read-only.

A common example is when the client only has one storage node in its affinity list and all devices on that storage node are disabled.

You must fix the problem and restart the backup. To fix the problem:

• Enable devices on one of the storage nodes on the client's list.

• Correct the pool restrictions for the devices on the storage node list.

• Add another storage node to the list that has enabled devices meeting the pool restrictions.

• Set one of the devices to read/write.

• Adjust the Save Mount Timeout and Save Lockout attributes for the storage node's Devices resource. For more information, see the online help.