Vmmaxbackupsessions

Edit online

The vmmaxbackupsessions option specifies the maximum number of IBM Storage Protect server sessions that send virtual machine (VM) data to the server that can be included in an optimized backup operation.

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

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

Supported clients

This option can be used with data movers on Windows Server 2012 R2, Windows Server 2016 and later operating systems. This option is not supported for data movers on Windows Server 2012.

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 in a client option set on the IBM Storage Protect server.

Syntax

Parameters

integer

Specifies the maximum number of IBM Storage Protect server sessions that can be created during the backup operation. The default is 4. The maximum is 100.

Tip: When you use the configuration wizard to configure Data Protection for Microsoft Hyper-V, the default is 16. This value is automatically updated in the data mover options file.

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

vmmaxparallel

The vmmaxparallel option specifies the maximum number of VMs that can be backed up to the IBM Storage Protect server at any one time. The value of the vmmaxbackupsessions option must be equal to or greater than the value of the vmmaxparallel option.

If the value is less than the value of the vmmaxparallel option, the following message is returned and the value is changed to the same value as the vmmaxparallel option:

ANS9995W The value of the VMMAXBACKUPSESSIONS option is number_value. 
This value must be greater than or equal to the value of the 
VMMAXPARALLEL option, which is number_value. The value will be 
set to 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 Storage 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: VMMAXBACKUPS 10
Command line:: dsmc backup vm -VMMAXBACKUPS=10