What is the right the procedure to set the numfsbufs parameter?

The current value of the parameter is 196

App_Server:>ioo -o numfsbufs 
numfsbufs = 196

The details of the server (prtconf command) are at http://dpaste.com/1317430/

We want to change the value of numfsbufs parameter to 512

This is based on the analysis of increasing value of I/O blocked

           52534 pending disk I/Os blocked with no pbuf
                0 paging space I/Os blocked with no psbuf
             2228 filesystem I/Os blocked with no fsbuf
                0 client filesystem I/Os blocked with no fsbuf
           313699 external pager filesystem I/Os blocked with no fsbuf

The command to do this is ioo -p -o numfsbufs=512

What I am not sure about is how to handle the mount/unmount of Volume Groups

Do i need to mount and unmount each and every file system? Or can i just restart the server after setting this variable and it will take care of itself

The link at http://dpaste.com/1317412/ shows the various volume groups.

Please guide as I am confused what the procedure should be.

The system administrators are asking a detailed set of instruction and hence I am trying to work out a document detailing the various steps.


That setting is clearly indicated as type 'Mount'.

The man page for ioo shows the types, including Mount

Mount - If changes to the parameter are only effective for future file systems or directory mounts

So, as long as you use -p on the ioo command, you can unmount and remount filesystems for the parameter to take effect. If you can't unmount the filesystems, then you will need to reboot, and then the parameter will take effect.

  • Thanks EightBitTony... I opted for a restart of the server after changing the parameter value.
    – Guddu
    Jul 30 '13 at 4:40

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