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[edit] aio0

The aio0 device on AIX provides "legacy" asynchronous I/O support (ie. not POSIX aio). It is still used by many products, including Oracle and DB2.

Important parameters:

autoconfig

Should be "available" on any system using aio.

maxreqs

The maximum total number of aio requests that may be outstanding at any point in time. For large transactional databases, this may need to be greatly increased.

maxservers

When multiplied by the number of logical CPUs (ie. with SMT, it is double the number of virtual processors), represents the maximum number of AIX aio server kernel threads (aioserver) that may be running at any time. This also represents the maximum number of aio-generated I/Os that may be outstanding to the disk subsystem at any time.