aio_max_ops

aio_max_ops specifies the system-wide maximum number of POSIX asynchronous I/O operations that can be queued simultaneously at any given time.

Acceptable Values:

Minimum
1
Maximum
0x100000
Default
2048

Specify integer value. For more information, see Specifying Parameter Values.

Description

This parameter places a limit on the system resources that can be consumed if a large number of POSIX asynchronous I/O operations are queued on the system at the same time. This parameter limits the ability of competing processes to overwhelm the system with large numbers of asynchronous I/O operations and the memory they require.

Each enqueued asynchronous operation requires allocation of system memory for its internal control structure, thus making this limit necessary. In addition to the system-wide limit, there is a per-process limit that is controlled using the argument RLIMIT_AIO_OPS to getrlimit() and setrlimit() calls.

aio_listio_max limits the number of operations that can be contained in a single listio() call from a given process, and the value of aio_max_ops must be sufficient to meet the reasonable needs of all processes that are making simultaneous or nearly simultaneous listio() calls without jeopardizing overall system balance.

For more information about POSIX asynchronous I/O, see the HP-UX Reference entry aio(5).

Additional Information