Out-of-space errors on VMware datastores

To prevent out-of-space errors during virtual machine backups, you can set a data usage threshold for VMware datastores by using the vmdatastorethreshold option.

Use the vmdatastorethreshold option to the set the threshold percentage of space usage for each VMware datastore of a virtual machine. When you initiate a virtual machine backup, the client checks the data usage of the VMware datastores before the virtual machine snapshot is created. If the threshold is exceeded in any of the VMware datastores, the virtual machine is not backed up.

For example, virtual machine vm1 spans datastore1 and datastore2. You can issue the following command to ensure that the VMware datastores of a virtual machine are at most 90% full before the virtual machine is backed up:

dsmc backup vm vm1 -vmdatastorethreshold=90

As a result, the client checks the space usage of both datastore1 and datastore2 before the snapshot operation begins. If the space usage of either VMware datastore exceeds the 90% threshold, the backup request for vm1 is not started.

Requirements:

Ensure that the threshold is low enough so that the snapshot does not use up all the available space in the VMware datastores. Otherwise, you will run out of space on the VMware datastores and the snapshot will not be created.
If you use multiple clients that act as data mover nodes, you must add the vmdatastorethreshold option to the options file for each data mover.

The client checks the data usage of the VMware datastore that contains the virtual machine disk snapshots. By default, the snapshots are created in the same directory as that of the parent virtual disk (.vmdk) file. The client checks the data usage only in the default location.

If you use the EXCLUDE.VMDISK option to exclude one or more disks from a backup, the threshold check is still run on these disks. Even though these disks are not backed up, VMware still takes a snapshot of these disks.

Independent disks are not checked during space verification processing because a snapshot of these disks does not use any VMware datastore space.

For more information about the vmdatastorethreshold option, see Vmdatastorethreshold.