OnlineJFS Sudden Performance Increase

[Chris Naudé]

We recently had an issue on our HP-UX 11.11 systems where OnlineJFS was disabled. The license expired after a reboot.

During the time while running with OnlineJFS disabled our Oracle backups were taking 12 hours to complete.

Our mount options looked like this:
/d15db on /dev/vgd15db/lvol1 delaylog,nodatainlog,largefiles

Two days ago we got the license sorted out and got OnlineJFS enabled again. We did nothing else with the system after simply enabling OnlineJFS. Immediately after doing this our backups started finishing in 3 instead of 12. Almost every database running on the system saw an increase in performance.

Does anyone have any idea why installing OnlineJFS would increase IO performance like this? I thought that we would need to unmount and remount the file systems with tuning options... We're totally perplexed by this.

[Robert-Jan Goossens_1 · Accepted solution]

Chris, the delaylog and nodatainlog are option included in the OnlineJFS licence product. Because the license expired these option will have a negative affect on the performance.

After you enabled the license these where simply available again.

Regards,
Robert-Jan

[Chris Naudé]

Excellent answer.

I do have a couple more questions regarding this.

Is there any documentation that supports what you have said?

I know for a fact that several options will cause the mount command to fail when OnlineJFS isn't available. These commands specifically would cause the mount to fail and we had to exclude them from our scripts: ,mincache=direct,convosync=direct

If I'm understanding this correctly the 'delaylog,nodatainlog' options don't cause mount to fail, but will have negative impact on performance when mounting without OnlineJFS.

Does that sound about right?

[Pete Randall]

See the man page for mount_vxfs:

datainlog|nodatainlog
Generally, VxFS does O_SYNC or O_DSYNC writes by logging the data and the time change to the inode (datainlog). If the nodatainlog option is used, the logging of synchronous writes is disabled; O_SYNC writes the data into the file and updates the inode synchronously before returning to the user.

NOTE: The datainlog option is available only with the HP OnLineJFS product.


Pete

[Robert-Jan Goossens_1]

http://forums11.itrc.hp.com/service/forums/questionanswer.do;HP-FORUMS-S-WPA-IDX=HnwTqr2dJ8KpbxKkBndTZDPqrK2QFvZVlJShtwSrwnKn41pRP1vH!1485543207!-1725100913?threadId=1143643

No I can't find a official doc but in the above thread you will find more info.

Regards,
Robert-Jan

[Robert-Jan Goossens_1]

A better one.

http://forums11.itrc.hp.com/service/forums/questionanswer.do?admit=109447626+1203610730249+28353475&threadId=1144586

[Steven E. Protter]

Shalom,

You can now that you are licensed, marginally improve performance with OnlineJFS vxfs defragmentation.


While it runs it hammers performance.

SEP

[Chris Naudé]

This is exactly the information I was looking for. Thanks for all of the answers.