aio(F)
aio --
asynchronous I/O tunable parameters
Description
The Asynchronous I/O (AIO) facility is an installable
package typically used by special purpose applications, such as
database servers. There are a set of parameters in the mtune file
associated with AIO; if necessary (for example, console
messages indicate running out of AIO resources), these
can be altered by using
idtune(ADM).
The major tunable parameters are as follows:
NAIOPROC-
The number of processes which may be simultaneously doing
AIO. The default value is 5.
NAIOREQ-
The maximum number of pending AIO requests. The default value
is 120.
NAIOREQPP-
The maximum number of AIO requests that a single process can
have pending. The default value is 120, meaning that one process can
potentially exhaust all AIO resources.
The AIO tunable parameters that follow are unlikely to need
changing, but are documented here for completeness:
NAIOBUF-
The number of AIO buffers. In the current implementation, this should
always be set to the same value as NAIOREQ.
NAIOHBUF-
The number of AIO hash queues (internal).
NAIOLOCKTBL-
Number of entries in the internal kernel table for AIO lock
permissions. The default value is 10. If there are many entries
in the /usr/lib/aiomemlock file, this number might need to be
increased.
Note that in order to use the AIO facility,
the system administrator must configure it into the system using
mkdev aio. See
mkdev(ADM)
for further details.
Files
/usr/include/sys/async.h-
definitions for asynchronous I/O
/usr/lib/aiomemlock-
permissions file to control how much memory can be locked by whom
/etc/aiolkinit-
command to lock physical memory for AIO transfers
/usr/bin/aioinfo-
command to print statistics on AIO usage
See also
aio(F),
aio(HW),
aioinfo(ADM),
aiolkinit(ADM),
aiomemlock(F),
idtune(ADM),
mkdev(ADM),
mtune(F),
stune(F)
© 2005 The SCO Group, Inc. All rights reserved.
SCO OpenServer Release 6.0.0 -- 03 June 2005