NUMOPENVOLSALLOWED

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The NUMOPENVOLSALLOWED option specifies the number of input FILE volumes in a deduplicated storage pool that can be open at one time.

Input volumes contain data to be read during client-restore operations and server processes, such as reclamation and migration. Use this option to improve performance by reducing the frequency with which volumes are opened and closed.

Each session within a client operation or server process can have as many open FILE volumes as specified by this option. A session is initiated by a client operation or by a server process. Multiple sessions can be started within each.

During a client restore operation, volumes can remain open for the duration of a client restore operation and as long a client session is active. During a no-query restore operation, the volumes remain open until the no-query restore completes. At that time, all volumes are closed and released. However, for a classic restore operation started in interactive mode, the volumes might remain open at the end of the restore operation. The volumes are closed and released when the next classic restore operation is requested.

Set this value in the server options file or use the SETOPT command.

Tip: This option can significantly increase the number of volumes and mount points in use at any one time. To optimize performance, follow these steps:
  • To set NUMOPENVOLSALLOWED, select a beginning value (the default is recommended). Monitor client sessions and server processes. Note the highest number of volumes open for a single session or process. Increase the setting of NUMOPENVOLSALLOWED if the highest number of open volumes is equal to the value specified by NUMOPENVOLSALLOWED.
  • To prevent sessions or processes from having to wait for a mount point, increase the value of the MOUNTLIMIT parameter in the device-class definition. Set the value of the MOUNTLIMIT parameter high enough to allow all client sessions and server processes using deduplicated storage pools to open the number of volume specified by the NUMOPENVOLSALLOWED option. For client sessions, check the destination in the copy group definition to determine how many nodes are storing data in the deduplicated storage pool. For server processes, check the number of processes allowed for each process for the storage pool.
  • A situation might occur in which a node backs up and restores or archives and retrieves concurrently to and from a deduplicated storage pool. All the mount points required for these operations increase the total number of mount points required by the node.

    As a result, the node might not be able to start additional backup sessions if it already has more mount points open than what the MAXNUMMP parameter in the client-node definition allows. This can occur even though the MOUNTLIMIT for the device class was not exceeded.

    To prevent backup and retrieve operations from failing, set the value of the MAXNUMMP parameter in the client-node definition to a value at least as high as the NUMOPENVOLSALLOWED option. Increase this value if you notice that the node is failing backup or retrieve operations because the MAXNUMMP value is being exceeded.

Syntax

Read syntax diagramSkip visual syntax diagramNUMOPENVOLSallowednumber_of_open_volumes

Parameters

number_of_open_volumes
Specifies the number of input FILE volumes in a deduplicated storage pool that can be open at one time. The default is 10. The minimum value is 3. The maximum value is 999.

Examples

Specify that up to 5 volumes in a deduplicated storage pool can be open at one time.

numopenvolsallowed 5