it-rex
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aix concurrent io 5.3
We have an AIX 5.3 that hosts our database .we would like to confirm that we have concurrent IO enabled how would we check that?
ASKER
how does this look like
mount
node mounted mounted over vfs date options
-------- --------------- --------------- ------ ------------ ---------------
/dev/hd4 / jfs2 Jan 15 23:07 rw,log=/dev/hd8
/dev/hd2 /usr jfs2 Jan 15 23:07 rw,log=/dev/hd8
/dev/hd9var /var jfs2 Jan 15 23:07 rw,log=/dev/hd8
/dev/hd3 /tmp jfs2 Jan 15 23:07 rw,log=/dev/hd8
/dev/hd1 /home jfs2 Jan 15 23:10 rw,log=/dev/hd8
/proc /proc procfs Jan 15 23:10 rw
/dev/hd10opt /opt jfs2 Jan 15 23:10 rw,log=/dev/hd8
/dev/fslv00 /slac jfs2 Jan 15 23:10 rw,log=/dev/hd8
/dev/lv245001 /u001 jfs2 Jan 15 23:10 rw,log=/dev/loglv00
/dev/lv245004 /u006 jfs2 Jan 15 23:10 rw,log=/dev/loglv03
/dev/lv245005 /u004 jfs2 Jan 15 23:10 rw,rbw,rbr,log=/dev/loglv0 4
/dev/fslv01 /esm jfs2 Jan 15 23:10 rw,log=/dev/loglv03
/dev/lv245002 /u005 jfs2 Jan 15 23:10 rw,log=/dev/loglv01
/dev/lv245003 /u015 jfs2 Jan 15 23:10 rw,log=/dev/loglv02
/dev/lv003 /u003 jfs2 Jan 15 23:10 rw,log=/dev/fsfsfsfsfsfsfs f
/dev/lv245010 /u010 jfs2 Jan 15 23:10 rw,log=/dev/loglv05
/dev/lv245013 /u013 jfs2 Jan 15 23:10 rw,log=/dev/loglv06
/shared /shared nfs3 Jan 15 23:10 rw,bg,soft,intr,vers=3,sec =sys
lsfs -q
Name Nodename Mount Pt VFS Size Options Auto Accounting
/dev/hd4 -- / jfs2 1048576 -- yes no
/dev/hd1 -- /home jfs2 3604480 -- yes no
/dev/hd2 -- /usr jfs2 4980736 -- yes no
/dev/hd9var -- /var jfs2 2097152 -- yes no
/dev/hd3 -- /tmp jfs2 2097152 -- yes no
/proc -- /proc procfs -- -- yes no
/dev/hd10opt -- /opt jfs2 720896 -- yes no
/dev/fslv00 -- /slac jfs2 4194304 rw yes no
/shared xxxxxxx /shared nfs -- rw,bg,soft,intr,vers=3,sec =sys yes no
/dev/lv245001 -- /u001 jfs2 62062592 rw yes no
/dev/lv245004 -- /u006 jfs2 20807680 rw yes no
/dev/lv245005 -- /u004 jfs2 418250752 rbrw,rw yes no
/dev/fslv01 -- /esm jfs2 3375104 rw yes no
/dev/lv245002 -- /u005 jfs2 62259200 rw yes no
/dev/lv245003 -- /u015 jfs2 62259200 rw yes no
/dev/lv003 -- /u003 jfs2 19321585664 rw yes no
/dev/lv245010 -- /u010 jfs2 21466447872 rw yes no
/dev/lv245013 -- /u013 jfs2 2100035584 rw yes no
mount
node mounted mounted over vfs date options
-------- --------------- --------------- ------ ------------ ---------------
/dev/hd4 / jfs2 Jan 15 23:07 rw,log=/dev/hd8
/dev/hd2 /usr jfs2 Jan 15 23:07 rw,log=/dev/hd8
/dev/hd9var /var jfs2 Jan 15 23:07 rw,log=/dev/hd8
/dev/hd3 /tmp jfs2 Jan 15 23:07 rw,log=/dev/hd8
/dev/hd1 /home jfs2 Jan 15 23:10 rw,log=/dev/hd8
/proc /proc procfs Jan 15 23:10 rw
/dev/hd10opt /opt jfs2 Jan 15 23:10 rw,log=/dev/hd8
/dev/fslv00 /slac jfs2 Jan 15 23:10 rw,log=/dev/hd8
/dev/lv245001 /u001 jfs2 Jan 15 23:10 rw,log=/dev/loglv00
/dev/lv245004 /u006 jfs2 Jan 15 23:10 rw,log=/dev/loglv03
/dev/lv245005 /u004 jfs2 Jan 15 23:10 rw,rbw,rbr,log=/dev/loglv0
/dev/fslv01 /esm jfs2 Jan 15 23:10 rw,log=/dev/loglv03
/dev/lv245002 /u005 jfs2 Jan 15 23:10 rw,log=/dev/loglv01
/dev/lv245003 /u015 jfs2 Jan 15 23:10 rw,log=/dev/loglv02
/dev/lv003 /u003 jfs2 Jan 15 23:10 rw,log=/dev/fsfsfsfsfsfsfs
/dev/lv245010 /u010 jfs2 Jan 15 23:10 rw,log=/dev/loglv05
/dev/lv245013 /u013 jfs2 Jan 15 23:10 rw,log=/dev/loglv06
/shared /shared nfs3 Jan 15 23:10 rw,bg,soft,intr,vers=3,sec
lsfs -q
Name Nodename Mount Pt VFS Size Options Auto Accounting
/dev/hd4 -- / jfs2 1048576 -- yes no
/dev/hd1 -- /home jfs2 3604480 -- yes no
/dev/hd2 -- /usr jfs2 4980736 -- yes no
/dev/hd9var -- /var jfs2 2097152 -- yes no
/dev/hd3 -- /tmp jfs2 2097152 -- yes no
/proc -- /proc procfs -- -- yes no
/dev/hd10opt -- /opt jfs2 720896 -- yes no
/dev/fslv00 -- /slac jfs2 4194304 rw yes no
/shared xxxxxxx /shared nfs -- rw,bg,soft,intr,vers=3,sec
/dev/lv245001 -- /u001 jfs2 62062592 rw yes no
/dev/lv245004 -- /u006 jfs2 20807680 rw yes no
/dev/lv245005 -- /u004 jfs2 418250752 rbrw,rw yes no
/dev/fslv01 -- /esm jfs2 3375104 rw yes no
/dev/lv245002 -- /u005 jfs2 62259200 rw yes no
/dev/lv245003 -- /u015 jfs2 62259200 rw yes no
/dev/lv003 -- /u003 jfs2 19321585664 rw yes no
/dev/lv245010 -- /u010 jfs2 21466447872 rw yes no
/dev/lv245013 -- /u013 jfs2 2100035584 rw yes no
ASKER CERTIFIED SOLUTION
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ASKER
so we do not have this benefit here ummm!!
so what exactly is the difference between concurrent IO and async IO?
is it worth enableing in busy systems?
so what exactly is the difference between concurrent IO and async IO?
is it worth enableing in busy systems?
ASKER
is it the same at this system too
mount
node mounted mounted over vfs date options
-------- --------------- --------------- ------ ------------ ---------------
/dev/hd4 / jfs2 Oct 19 23:09 rw,log=/dev/hd8
/dev/hd2 /usr jfs2 Oct 19 23:09 rw,log=/dev/hd8
/dev/hd9var /var jfs2 Oct 19 23:09 rw,log=/dev/hd8
/dev/hd3 /tmp jfs2 Oct 19 23:09 rw,log=/dev/hd8
/dev/hd1 /home jfs2 Oct 19 23:09 rw,log=/dev/hd8
/proc /proc procfs Oct 19 23:09 rw
/dev/hd10opt /opt jfs2 Oct 19 23:09 rw,log=/dev/hd8
/dev/slaclv /slac jfs2 Oct 19 23:09 rw,log=/dev/hd8
/dev/lv2951011 /esm jfs2 Oct 19 23:09 rw,log=/dev/loglv00
/dev/lv2951012 /home/axway jfs2 Oct 19 23:09 rw,log=/dev/loglv00
/dev/lv2951013 /axway jfs2 Oct 19 23:09 rw,log=/dev/loglv00
/dev/lv2951014 /xip jfs2 Oct 19 23:09 rw,log=/dev/loglv00
/dev/lv2951015 /u001 jfs2 Oct 19 23:09 rw,log=/dev/loglv00
/dev/lv2951071 /u020 jfs2 Oct 19 23:09 rw,log=INLINE
/dev/lv2951031 /u003 jfs2 Oct 19 23:27 rw,log=/dev/fsfsfsfsloglv0 2
/dev/lv2951051 /u010 jfs2 Oct 19 23:27 rw,log=/dev/lv00
/dev/lv2951021 /u002 jfs2 Oct 19 23:37 rw,log=/dev/loglv01
/dev/lv2951023 /u004 jfs2 Oct 19 23:37 rw,rbw,rbr,log=/dev/loglv0 1
/dev/lv2951024 /u005 jfs2 Oct 19 23:37 rw,log=/dev/loglv01
/dev/ls2951026 /u007 jfs2 Oct 19 23:37 rw,log=/dev/loglv01
/dev/lv2951025 /u015 jfs2 Oct 19 23:37 rw,log=/dev/loglv01
/dev/lv2951061 /x001 jfs2 Oct 19 23:37 rw,log=INLINE
/dev/lv2951042 /u102 jfs2 Oct 19 23:37 rw,log=/dev/loglv03
/dev/lv2951041 /u103 jfs2 Oct 19 23:37 rw,log=/dev/loglv03
/dev/lv2951043 /u104 jfs2 Oct 19 23:37 rw,rbw,rbr,log=/dev/loglv0 3
/dev/lv2951044 /u105 jfs2 Oct 19 23:37 rw,log=/dev/loglv03
/dev/lv2951046 /u110 jfs2 Oct 19 23:37 rw,log=/dev/loglv03
/dev/lv2951045 /u115 jfs2 Oct 19 23:37 rw,log=/dev/loglv03
/dev/lv2951022 /home/ jfs2 Dec 12 13:04 rw,log=INLINE
lsfs -q
Name Nodename Mount Pt VFS Size Options Auto Accounting
/dev/hd4 -- / jfs2 1048576 -- yes no
/dev/hd4: Permission denied
/dev/hd1 -- /home jfs2 5177344 -- yes no
/dev/hd1: Permission denied
/dev/hd2 -- /usr jfs2 7536640 -- yes no
/dev/hd2: Permission denied
/dev/hd9var -- /var jfs2 3342336 -- yes no
/dev/hd9var: Permission denied
/dev/hd3 -- /tmp jfs2 4194304 -- yes no
/dev/hd3: Permission denied
/proc -- /proc procfs -- -- yes no
/dev/hd10opt -- /opt jfs2 2097152 -- yes no
/dev/hd10opt: Permission denied
/dev/livedump -- /var/adm/ras/livedump jfs2 524288 -- yes no
/dev/livedump: Permission denied
/dev/slaclv -- /slac jfs2 4194304 rw yes no
/dev/slaclv: Permission denied
/dev/lv2951011 -- /esm jfs2 3145728 rw yes no
/dev/lv2951011: Permission denied
/dev/lv2951012 -- /home/axway jfs2 3145728 rw yes no
/dev/lv2951012: Permission denied
/dev/lv2951013 -- /axway jfs2 3145728 rw yes no
/dev/lv2951013: Permission denied
/dev/lv2951014 -- /xip jfs2 3145728 rw yes no
/dev/lv2951014: Permission denied
/dev/lv2951015 -- /u001 jfs2 88342528 rw yes no
/dev/lv2951015: Permission denied
/shared sy02131 /shared nfs -- bg,intr,vers=4,sec=sys yes no
/dev/lv2951021 -- /u002 jfs2 65011712 rw no no
/dev/lv2951021: Permission denied
/dev/lv2951023 -- /u004 jfs2 591396864 rbrw,rw no no
/dev/lv2951023: Permission denied
/dev/lv2951024 -- /u005 jfs2 60817408 rw no no
/dev/lv2951024: Permission denied
/dev/lv2951025 -- /u015 jfs2 60817408 rw no no
/dev/lv2951025: Permission denied
/dev/lv2951041 -- /u103 jfs2 200015872 rw no no
/dev/lv2951041: Permission denied
/dev/lv2951042 -- /u102 jfs2 40108032 rw no no
/dev/lv2951042: Permission denied
/dev/lv2951043 -- /u104 jfs2 60030976 rbrw,rw no no
/dev/lv2951043: Permission denied
/dev/lv2951044 -- /u105 jfs2 40108032 rw no no
/dev/lv2951044: Permission denied
/dev/lv2951045 -- /u115 jfs2 40108032 rw no no
/dev/lv2951045: Permission denied
/dev/lv2951046 -- /u110 jfs2 200015872 rw no no
/dev/lv2951046: Permission denied
/dev/ls2951026 -- /u007 jfs2 10485760 rw no no
/dev/ls2951026: Permission denied
/dev/lv2951061 -- /x001 jfs2 1046478848 rw no no
/dev/lv2951061: Permission denied
/dev/lv2951071 -- /u020 jfs2 2096103424 -- yes no
/dev/lv2951071: Permission denied
/dev/lv2951031 -- /u003 jfs2 8589934592 rw no no
/dev/lv2951031: Permission denied
/dev/lv2951051 -- /u010 jfs2 8589934592 rw no no
/dev/lv2951051: Permission denied
/dev/lv2951022 -- /home/mmfeed jfs2 10485760 rw no no
/dev/lv2951022: Permission denied
mount
node mounted mounted over vfs date options
-------- --------------- --------------- ------ ------------ ---------------
/dev/hd4 / jfs2 Oct 19 23:09 rw,log=/dev/hd8
/dev/hd2 /usr jfs2 Oct 19 23:09 rw,log=/dev/hd8
/dev/hd9var /var jfs2 Oct 19 23:09 rw,log=/dev/hd8
/dev/hd3 /tmp jfs2 Oct 19 23:09 rw,log=/dev/hd8
/dev/hd1 /home jfs2 Oct 19 23:09 rw,log=/dev/hd8
/proc /proc procfs Oct 19 23:09 rw
/dev/hd10opt /opt jfs2 Oct 19 23:09 rw,log=/dev/hd8
/dev/slaclv /slac jfs2 Oct 19 23:09 rw,log=/dev/hd8
/dev/lv2951011 /esm jfs2 Oct 19 23:09 rw,log=/dev/loglv00
/dev/lv2951012 /home/axway jfs2 Oct 19 23:09 rw,log=/dev/loglv00
/dev/lv2951013 /axway jfs2 Oct 19 23:09 rw,log=/dev/loglv00
/dev/lv2951014 /xip jfs2 Oct 19 23:09 rw,log=/dev/loglv00
/dev/lv2951015 /u001 jfs2 Oct 19 23:09 rw,log=/dev/loglv00
/dev/lv2951071 /u020 jfs2 Oct 19 23:09 rw,log=INLINE
/dev/lv2951031 /u003 jfs2 Oct 19 23:27 rw,log=/dev/fsfsfsfsloglv0
/dev/lv2951051 /u010 jfs2 Oct 19 23:27 rw,log=/dev/lv00
/dev/lv2951021 /u002 jfs2 Oct 19 23:37 rw,log=/dev/loglv01
/dev/lv2951023 /u004 jfs2 Oct 19 23:37 rw,rbw,rbr,log=/dev/loglv0
/dev/lv2951024 /u005 jfs2 Oct 19 23:37 rw,log=/dev/loglv01
/dev/ls2951026 /u007 jfs2 Oct 19 23:37 rw,log=/dev/loglv01
/dev/lv2951025 /u015 jfs2 Oct 19 23:37 rw,log=/dev/loglv01
/dev/lv2951061 /x001 jfs2 Oct 19 23:37 rw,log=INLINE
/dev/lv2951042 /u102 jfs2 Oct 19 23:37 rw,log=/dev/loglv03
/dev/lv2951041 /u103 jfs2 Oct 19 23:37 rw,log=/dev/loglv03
/dev/lv2951043 /u104 jfs2 Oct 19 23:37 rw,rbw,rbr,log=/dev/loglv0
/dev/lv2951044 /u105 jfs2 Oct 19 23:37 rw,log=/dev/loglv03
/dev/lv2951046 /u110 jfs2 Oct 19 23:37 rw,log=/dev/loglv03
/dev/lv2951045 /u115 jfs2 Oct 19 23:37 rw,log=/dev/loglv03
/dev/lv2951022 /home/ jfs2 Dec 12 13:04 rw,log=INLINE
lsfs -q
Name Nodename Mount Pt VFS Size Options Auto Accounting
/dev/hd4 -- / jfs2 1048576 -- yes no
/dev/hd4: Permission denied
/dev/hd1 -- /home jfs2 5177344 -- yes no
/dev/hd1: Permission denied
/dev/hd2 -- /usr jfs2 7536640 -- yes no
/dev/hd2: Permission denied
/dev/hd9var -- /var jfs2 3342336 -- yes no
/dev/hd9var: Permission denied
/dev/hd3 -- /tmp jfs2 4194304 -- yes no
/dev/hd3: Permission denied
/proc -- /proc procfs -- -- yes no
/dev/hd10opt -- /opt jfs2 2097152 -- yes no
/dev/hd10opt: Permission denied
/dev/livedump -- /var/adm/ras/livedump jfs2 524288 -- yes no
/dev/livedump: Permission denied
/dev/slaclv -- /slac jfs2 4194304 rw yes no
/dev/slaclv: Permission denied
/dev/lv2951011 -- /esm jfs2 3145728 rw yes no
/dev/lv2951011: Permission denied
/dev/lv2951012 -- /home/axway jfs2 3145728 rw yes no
/dev/lv2951012: Permission denied
/dev/lv2951013 -- /axway jfs2 3145728 rw yes no
/dev/lv2951013: Permission denied
/dev/lv2951014 -- /xip jfs2 3145728 rw yes no
/dev/lv2951014: Permission denied
/dev/lv2951015 -- /u001 jfs2 88342528 rw yes no
/dev/lv2951015: Permission denied
/shared sy02131 /shared nfs -- bg,intr,vers=4,sec=sys yes no
/dev/lv2951021 -- /u002 jfs2 65011712 rw no no
/dev/lv2951021: Permission denied
/dev/lv2951023 -- /u004 jfs2 591396864 rbrw,rw no no
/dev/lv2951023: Permission denied
/dev/lv2951024 -- /u005 jfs2 60817408 rw no no
/dev/lv2951024: Permission denied
/dev/lv2951025 -- /u015 jfs2 60817408 rw no no
/dev/lv2951025: Permission denied
/dev/lv2951041 -- /u103 jfs2 200015872 rw no no
/dev/lv2951041: Permission denied
/dev/lv2951042 -- /u102 jfs2 40108032 rw no no
/dev/lv2951042: Permission denied
/dev/lv2951043 -- /u104 jfs2 60030976 rbrw,rw no no
/dev/lv2951043: Permission denied
/dev/lv2951044 -- /u105 jfs2 40108032 rw no no
/dev/lv2951044: Permission denied
/dev/lv2951045 -- /u115 jfs2 40108032 rw no no
/dev/lv2951045: Permission denied
/dev/lv2951046 -- /u110 jfs2 200015872 rw no no
/dev/lv2951046: Permission denied
/dev/ls2951026 -- /u007 jfs2 10485760 rw no no
/dev/ls2951026: Permission denied
/dev/lv2951061 -- /x001 jfs2 1046478848 rw no no
/dev/lv2951061: Permission denied
/dev/lv2951071 -- /u020 jfs2 2096103424 -- yes no
/dev/lv2951071: Permission denied
/dev/lv2951031 -- /u003 jfs2 8589934592 rw no no
/dev/lv2951031: Permission denied
/dev/lv2951051 -- /u010 jfs2 8589934592 rw no no
/dev/lv2951051: Permission denied
/dev/lv2951022 -- /home/mmfeed jfs2 10485760 rw no no
/dev/lv2951022: Permission denied
Under CIO, multiple threads may simulteanously perform reads and writes
on a shared file.
Applications must be able to enforce serialization when using CIO,
to avoid possible data corruption or performance issues.
Most, if not all, database servers do serialization on their own and can use CIO for their datafiles and redo logs (NOT for binaries (!) or other regular files and archivelogs).
AIO implements quite a different mechanism.
Synchronous I/O requires a disk operation, and applications cannot continue until the I/O operation is complete.
Asynchronous I/O allows applications to perform read or write operations without being blocked, since all I/O operations are done in background.
I/O operations and application processing can thus run simultaneously which can give a huge performance gain (particularly with Oracle).
Asynchronous I/O on filesystems is handled through kernel processes
(aioserver), and each I/O is handled by a single kernel process. The minimum and maximum numbers of aioserver processes are configurable.
Oracle has ain initialization parameter DISK_ASYNCH_IO, and if this parameter is "TRUE" and if AIO is available Oracle uses AIO transparently without further notification or the like.
Check whether AIO is available and configured with
lsattr -El aio0
"autoconfig" must be "available", otherwise ("defined") AIO is disabled.
To change the state from "defined" to "available" run
chdev -l aio0 -a autoconfig=available
cfgmgr # or "mkdev -l aio0"
On older 5.3 systems you must run
chdev -l aio0 - P -a autoconfig=available
and reboot.
Check the number of running aioservers (if any) with
ps -kf | grep aio
Once AIO is enabled CIO will have (almost) no effect, so, at least for Oracle, forget it.
There might be databases which do not check for or cannot use AIO, so CIO could be an option here.
Please consult the documentation shipped by the manufacturer of your DB system.
And yes, the second system you showed doesn't use CIO either.
wmp
on a shared file.
Applications must be able to enforce serialization when using CIO,
to avoid possible data corruption or performance issues.
Most, if not all, database servers do serialization on their own and can use CIO for their datafiles and redo logs (NOT for binaries (!) or other regular files and archivelogs).
AIO implements quite a different mechanism.
Synchronous I/O requires a disk operation, and applications cannot continue until the I/O operation is complete.
Asynchronous I/O allows applications to perform read or write operations without being blocked, since all I/O operations are done in background.
I/O operations and application processing can thus run simultaneously which can give a huge performance gain (particularly with Oracle).
Asynchronous I/O on filesystems is handled through kernel processes
(aioserver), and each I/O is handled by a single kernel process. The minimum and maximum numbers of aioserver processes are configurable.
Oracle has ain initialization parameter DISK_ASYNCH_IO, and if this parameter is "TRUE" and if AIO is available Oracle uses AIO transparently without further notification or the like.
Check whether AIO is available and configured with
lsattr -El aio0
"autoconfig" must be "available", otherwise ("defined") AIO is disabled.
To change the state from "defined" to "available" run
chdev -l aio0 -a autoconfig=available
cfgmgr # or "mkdev -l aio0"
On older 5.3 systems you must run
chdev -l aio0 - P -a autoconfig=available
and reboot.
Check the number of running aioservers (if any) with
ps -kf | grep aio
Once AIO is enabled CIO will have (almost) no effect, so, at least for Oracle, forget it.
There might be databases which do not check for or cannot use AIO, so CIO could be an option here.
Please consult the documentation shipped by the manufacturer of your DB system.
And yes, the second system you showed doesn't use CIO either.
wmp
ASKER
I will open a new Q about async IO ..so I can give you ,deserved points.
now we do not have CIO on both 1st system 5.3 and 1nd system 7.1
both are Oracle database servers. is it true that although both systems are mounted with no CIO option Oracle can still do CIO on its own if
filesystemio_options='seta ll'
this issue is scattered over the place and no single assured fact,some say u do not need to set it on the filesystem anymore and some say the opposite.
and even if this is correct is it correct for both
5.3 and 7.1?
thanks alot
now we do not have CIO on both 1st system 5.3 and 1nd system 7.1
both are Oracle database servers. is it true that although both systems are mounted with no CIO option Oracle can still do CIO on its own if
filesystemio_options='seta
this issue is scattered over the place and no single assured fact,some say u do not need to set it on the filesystem anymore and some say the opposite.
and even if this is correct is it correct for both
5.3 and 7.1?
thanks alot
The parameter filesystemio_options which in a way replaced the old DISK_ASYNCH_IO initialization parameter governs AIO and Direct I/O, but not Concurrent I/O!
'setall' enables both direct I/O and asynchronous I/O where possible.
And yes, that's the same for AIX 5, 6 and 7.
AIX 6 changed the implementation of AIO (no more device "aio0") and the way how to configure AIO ("ioo" instead of "chdev") but the underlying mechanisms are still the same.
In regard to DIO and CIO nothing has changed at all.
'setall' enables both direct I/O and asynchronous I/O where possible.
And yes, that's the same for AIX 5, 6 and 7.
AIX 6 changed the implementation of AIO (no more device "aio0") and the way how to configure AIO ("ioo" instead of "chdev") but the underlying mechanisms are still the same.
In regard to DIO and CIO nothing has changed at all.
ASKER
So final word no CIO on file system..
no CIO in Oracle although the affored mentioned parameter is set.
Correct?
no CIO in Oracle although the affored mentioned parameter is set.
Correct?
Yes.
ASKER
undisputed woolmilkporc is the best expert here..
and probably the best AIX admin I have ever came across..
PERIOD.
and probably the best AIX admin I have ever came across..
PERIOD.
mount
You should see "cio" in the "options" column for a concurrent I/O enabled filesystem.
lsfs -q
should also have that info,
and the /etc/filesystems file should have "cio" in the "options" field under the relevant filesystem stanza if this options is to be used by default.
I/O on files opened in a file system mounted that way will behave as if the files had been opened with O_CIO specified in the open() system call.
Performing CIO on files opened without that option consequently requires that these files were opened with O_CIO specified in the open() system call by your database application. This cannot easily be checked by means of OS commands.
However, for example Oracle (as opposed to e.g. Informix) has no builtin CIO feature, so to make Oracle perform CIO on Oracle datafiles you must explicitly mount the relevant FS with CIO.