Vijay Adik vadik@us - IBM

54
IBM Advanced Technical Support - Americas
Asynchronous I/O for filesystem environments
AIX parameters
minservers = minimum # of AIO server processes (system wide)
– AIX 5.3 default = 1 (system wide), 6.1 default = 3 (per CPU)
maxservers = maximum # of AIO server processes
– AIX 5.3 default = 10 (per CPU), 6.1 default = 30 (per CPU)
maxreqs = maximum # of concurrent AIO requests
– AIX 5.3 default = 4096, 6.1 default = 65536
“enable” at system restart (Always enabled for 6.1)
Typical 5.3 settings: minservers=100, maxservers=200, maxreqs=65536
– Raw Devices or ASM environments use fastpath AIO
> above parameters do not apply
> lsattr -El aio0 and look for the value "fastpath", which should be enabled
– CIO uses fastpath AIO in AIX 6.1
– For CIO fastpath AIO in 5.3 TL5+, set fsfastpath=1
> not persistent across reboot
Oracle parameters
disk_asynch_io = TRUE
filesystemio_options = {ASYNCH | SETALL}
db_writer_processes (let default)
© 2009 IBM Corporation
April 17, 2009