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
>>-NUMOPENVOLSallowed--number_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