Restoring a virtual disk using multiple sessions

To optimize performance for restore operations, multiple sessions can be used to restore a virtual disk.

Before you begin

To restore a virtual disk using multiple sessions, use the vmmaxrestoresessions option. This option specifies the maximum number of IBM Spectrum Protect server sessions that can be used in an optimized restore operation for a virtual disk.

Multiple session restores can be used under the following conditions:

The data to be restored is stored on several tape volumes or file device class volumes.
Sufficient mount points are available.

Note: This option is not valid for Hyper-V virtual machines backups.

About this task

Complete these steps on the data mover system:

Procedure

Start a command-line session:
- Open a command prompt and change to the directory: cd "C:\Program Files\IBM\SpectrumProtect\baclient".
- Open a terminal window and change to the directory: cd /opt/tivoli/tsm/client/ba/bin.
Open the dsm.opt file with your preferred text editor.
Enter the vmmaxrestoresessions option and one or more blank spaces, followed by the option value.
For example:
```
vmmaxrestoresessions 3
```
Issue the restore vm command.
For example:
```
dsmc restore vm vm1
```
Using the examples provided, the restore operations for virtual disks in the VM vm1 can use a maximum of 3 sessions.
Note: The maximum number of sessions that can be allocated to an individual disk being restored is based on the transport the disk was opened with. The following are the limits of a restore sessions number:
- For NBD and NBDSSL: 2 sessions
- For HOTADD and SAN: 4 sessions