topic Re: vxfs os buffering cache in Operating System - HP-UX

vxfs os buffering cache

perdida — Thu, 19 Jul 2007 09:39:18 GMT

Hello

How can i modify a filesystem so it uses database buffer cache rather than OS buffer cache?

Re: vxfs os buffering cache

A. Clay Stephenson — Thu, 19 Jul 2007 09:45:39 GMT

If you have OnlineJFS, use these vxfs mount options:

mincache=direct,convosync=direct,nodatainlog,delaylog

Man mount_vxfs for details.

Re: vxfs os buffering cache

Pete Randall — Thu, 19 Jul 2007 09:46:06 GMT

Use the raw device, for example /dev/vg01/rlvol1, rather than /dev/vg01/lvol1.

Pete

Re: vxfs os buffering cache

Sandman! — Thu, 19 Jul 2007 09:48:54 GMT

Use the raw device as opposed to the block device for storing database files. And if this is Oracle DB then the database buffer cache is inside your SGA.

~hope it helps

Re: vxfs os buffering cache

James R. Ferguson — Thu, 19 Jul 2007 09:48:56 GMT

Hi:

Mount your VxFS filesystem with:

# mincache=direct,convosync=direct

You need OnlineJFS for this to work, but you *should* have that for a multitude of reasons.

Regards!

...JRF...

Re: vxfs os buffering cache

perdida — Thu, 19 Jul 2007 10:22:02 GMT

Thanks for your quick reply, i have online jfs and the database filesystems are mounted as:
vxfs delaylog,largefiles 0 2

what are the correct steps to modify parameters to:
vxfsdelaylog,nodatainlog,largefiles,mincache=direct,convosync=direct 0 2

??

Re: vxfs os buffering cache

A. Clay Stephenson — Thu, 19 Jul 2007 10:34:03 GMT

Shutdown the database. Umount the applicable filesystems.

e.g.
umount /oradata/ora1
umount /oradata/ora2

Edit /etc/fstab to include your new mount options.

mount /oradata/ora1
mount /oradata/ora2

Restart the database.

Re: vxfs os buffering cache

perdida — Fri, 20 Jul 2007 04:35:23 GMT

Thanks for your help!