Vmmaxparallel

The vmmaxparallel option is used to configure parallel backups of several virtual machines (VMs) by using a single instance of the data mover. This option specifies the maximum number of VMs that can be backed up to the IBM Spectrum Protect server at a time.

An optimized backup operation is one in which parallel backup capability is enabled at the VM, virtual disk, or subdisk level.

The vmmaxparallel option works with the vmmaxbackupsessions option to optimize backup operations and to help control the amount of resources that the backup can create on a Hyper-V host. Adjust the values of these options to find the values that provide optimal performance for the backups that are in your environment.

Options file

This option is valid in the data mover options file (dsm.hostname_HV_DM.opt) or on the command line for use with the backup vm command. It can also be included on the server in a client option set.

Syntax

Parameters

integer

Specifies the maximum number of VMs that can be backed up at a time during a parallel backup operation. The default is 4. The maximum is 50.

Tip: When you use the configuration wizard in the Data Protection for Microsoft Hyper-V Management Console to configure Data Protection for Microsoft Hyper-V, the default is 8. This value is automatically updated in the data mover options file.

Tip: When using client-side data deduplication, a deduplication session is started for each VM. This deduplication session is not counted as one of the vmmaxparallel sessions.

Review the following information when you use the vmmaxparallel option in conjunction with the vmmaxbackupsessions option or the maxnummp server parameter:

vmmaxbackupsessions

The vmmaxbackupsessions specifies the maximum number of sessions that send VM data to the IBM Spectrum Protect server that can be included in an optimized backup operation. The value of the vmmaxbackupsessions option must be equal to or greater than the value of the vmmaxparallel option.

maxnummp

The maxnummp server parameter specifies the maximum number of mount points that a node is allowed to use on the IBM Spectrum Protect server when the copy destination of the storage pool is FILE or TAPE. The maxnummp parameter setting must be equal to or greater than the vmmaxparallel and vmmaxbackupsessions option settings. When multiple instances of the data mover are backing up files, or when a single data mover runs parallel backups, more mount points might be needed.

If the value for the vmmaxparallel or vmmaxbackupsessions option exceeds the value for the maxnummp parameter, ANS0266I and other messages are displayed. Depending on the message, the data mover reduces the value of the vmmaxparallel option to match the number that is specified by the maxnummp parameter or prohibits additional sessions from being opened for the specified VM. In either situation, the backup operation continues.

If additional ANS0266I errors are detected, the data mover reduces the vmmaxparallel value by 1 and attempts to continue the backup operation. If vmmaxparallel is decremented to 1 and more ANS0266I errors are generated, the backup operation is ended and the following error is issued:

ANS5228E A backup VM operation failed because VMMAXPARALLEL was reduced 
to 1 and the client still cannot obtain a server mount point.

If you want to increase the value for the maxnummp parameter so your node can support additional parallel backup sessions, contact your server administrator.

Examples

Options file: VMMAXP 10
Command line: dsmc backup vm -vmmaxp=10