NAME
msgmni — maximum number of system-wide System V IPC message queues (IDs) allowed
VALUES
Allowed Values
Minimum: 1
Maximum: 32767
DESCRIPTION
The
msgmni
tunable specifies the maximum number of system-wide System V IPC
message queue identifiers (one per queue).
Each message queue created has an identifier (ID) and there is an
upper limit of
msgmni
identifiers.
Applications use the
msgget()
system call to create new queues.
If all IDs have been used,
msgget()
will return
ENOSPC.
If a process acquires a message queue, but the process terminates
without removing it, the queue and all its messages remain.
Abandoned message queues can be removed with the
ipcrm
command.
Message queue status can be monitored using the
ipcs
command.
For more information about System V message queues, refer to the
"Overview" section of the
mesg(5)
manpage.
Who Is Expected to Change This Tunable?
Anyone.
Restrictions on Changing
Changes to this tunable take effect at the next reboot.
When Should the Value of This Tunable Be Raised?
Raise this tunable when applications require more queues.
When Should the Value of This Tunable Be Lowered?
Lower this tunable when the requirement for queues has diminished.
What Other Tunable Values Should Be Changed at the Same Time?
All the System V message queue tunables are interrelated and should
not
be treated as independent variables.
The set must be evaluated as a system to ensure the tunables reflect
the application requirements.
The
mesg
tunables include
msgmap,
msgmax,
msgmnb,
msgmni,
msgseg,
msgssz,
and
msgtql.
Specifically, the
msgseg
and
msgtql
tunables, may need adjustment along with changes to the
msgmni
tunable.
WARNINGS
All HP-UX kernel tunable parameters are release specific.
This parameter may be removed or have its meaning changed in
future releases of HP-UX.
AUTHOR
msgmni
was developed by AT&T.
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