>> AIO is supported for all jfs type file systems, even raw devices.

yes, that is correct, but donot get confused by aio subsystem and
aioservers, they are 2 different things ... from the docs

"If the disk drives that are being accessed asynchronously are using a
form of raw logical volume management, then the disk I/O is not routed
through the aios kprocs. In that case the number of servers running is
not relevant."

raw lv aio is implimented in the kernel and you cannot configure it
aioservers are for jfs and jfs2 and you can configure it with your
posix_aioservers and legacy aioservers

HTH
Mark Taylor