Vmmaxparallel

This option is used to configure parallel backups of several virtual machines by using a single instance of the backup-archive client. The vmmaxparallel option specifies the maximum number of virtual machines that can be backed up to the server, at any one time.

This option works together with the vmlimitperhost and vmlimitperdatastore options to optimize the performance of parallel backups, and to reduce the processor load that parallel backs can create on a host in the vSphere infrastructure.

Supported clients

Linux operating systems This option can be used with supported x86_64 Linux clients.

Windows operating systems This option can be used with supported Windows clients.

Options file

Linux operating systems This option is valid in the client system options file (dsm.sys) or on the command line for the Backup VM command. It can also be included on the server in a client options set. It cannot be set in the Preferences Editor.

Windows operating systems This option is valid in the client options file (dsm.opt) or on the command line for the Backup VM command. It can also be included on the server in a client options set. It cannot be set in the Preferences Editor.

Syntax


                  .-1-----------.   
>>-VMMAXParallel--+-+---------+-+------------------------------><
                    '-integer-'

Parameters

integer

Specifies the maximum number of virtual machines that can be backed up, at any one time, during a parallel backup operation. The default is 1. The maximum is 50.

Adjust the values of vmmaxparallel, vmlimitperhost, and vmlimitperdatastore to find the values that provide optimal performance for parallel backups, in your environment.

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

The MAXNUMMP server parameter specifies the maximum number of mount points a node is allowed to use on the server when the copy destination of the storage pool is FILE or TAPE. The MAXNUMMP parameter must be equal to or greater than the VMMAXPARALLELsetting. When multiple instances of the client are backing up files, or when a single client performs parallel backups, more mount points might be needed.

If the number of mount points that are requested exceeds the MAXNUMMP value, the server issues an error (ANS0266I). In response to the error, the client reduces VMMAXPARALLEL to match the number that is specified by MAXNUMMP and continues the backup with the reduced number of sessions. If additional ANS0266I errors are detected, the client reduces VMMAXPARALLEL by 1 and attempts to continue the backup. If VMMAXPARALLEL is decremented to 1 and the client receives more ANS0266I errors, the client ends the backup and issues the following error:

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

Contact your server administrator if you need the value that is currently set for MAXNUMMP increased, so your node can support additional parallel backup sessions.

Examples

Options file: VMMAXP 10