Originally posted by: ed_AIX

Hello,

Can JFS and JFS2 journal logging be disabled in AIX 5.3?

What command is used to accomplish this?

Thank you,

Edward Pluskwa
#AIX-Forum

Originally posted by: hdkutz

Hello ed AIX,
what problem are you trying to solve?
JFS = Journaled File System
JFS2 = Journaled File System Version 2
As you can see - both are "journaled" File Systems.
You cannot deactivate the journaling and you probably do not want it (recovery!).
Here are some good starting points for LVM in AIX.
http://www.redbooks.ibm.com/abstracts/sg245432.html?Open
http://www.redbooks.ibm.com/abstracts/sg245433.html?Open
http://www.redbooks.ibm.com/abstracts/redp0107.html?Open

Cheers,
ku
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Originally posted by: j.gann

jfs logging can be turned off via undocumented mount option (try google)
jfs2 logging cannot be turned off

Make sure you know what metadata integrity means before making a decision.
#AIX-Forum

Originally posted by: apple08

dear sir,
last 2 weeks during technical workshop, one guy said we don't need to create the jfs2 log if we are using ibm/hp san storage. i ask him why. he said we can leverage on vraid disc protection (more reliable). what do u say. hope to hear from you
thank you
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Originally posted by: j.gann

hello,

just as I wrote: "jfs2 logging cannot be turned off".
you can only choose to have your log INLINE within the FS or on a seperate LOG LV that can be used by more than one FS.
luckily this makes further discussion obsolete saving me from comparing logical level (filesystem integrity) to block level integrity...

best regards
#AIX-Forum

Originally posted by: hdkutz

Interesting.
Did you mean the freeze mount Option?
http://www-01.ibm.com/support/docview.wss?uid=isg1IY66043

Cheers,
ku
#AIX-Forum

Originally posted by: ed_AIX

Hello ku, everyone,

No, I didn't mean the freeze/thaw functions.

For our application we are trying to achieve the fastest filesystem I/O rates possible. I realize that JFS and JFS2 are journaled file systems and turning off or disabling the logging function makes them essentially "non-journaled" and our metadata is unprotected against failure. That is acceptable at this point.

Can AIX run a third-party non-journaled filesystem, similar to how Linux can? Where metadata logging is not needed?

Thanks,

Ed
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Originally posted by: orphy

I believe VxFS also lets you disable metadata logging.
Orphy
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Originally posted by: iulianr

hi
in aix 6 you can mount a filesystem with logging turned off:

mount -o log=NULL /<fs_name>

in AIX 5.3 it is not possible AFAIK.
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Originally posted by: j.gann

here is the info on disabling jfs journaling:
http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.prftungd/doc/prftungd/journaling.htm
hope you're aware that total data loss is possible.
might be worth to check with filemon if you fs journal really is used busily...
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Originally posted by: SystemAdmin

I guess I'll jump in and ask what the application is that requires fast I/O to a cooked file system, and how you know that the problem is directly related to the JFS/JFS2 logging implementation?

If the application is a database engine like Informix, DB2, or Oracle; you may want to check out the DIO (direct I/O) or CIO (concurrent I/O) flags at the file system level. IBM claims that pairing the CIO flag on the file system mount and some Oracle tuning parameters will give close to the performance level you'd find in raw logical volumes. I haven't done enough head-to-head comparisons to really prove or disprove that claim...

If the application isn't a database engine, could you give us an idea of what kind of work it's doing in the file system? Is it creating/deleting lots of files? Opening/modifying lots of files? Something else?

Thanks!

-Chris
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