memory page swapping

[Gary Yu]

Hi, I'm going to tuning the Buffer cache of Oracle running on my HPUX 11.0 box. Oracle suggest to increase the buffer cache it uses as much as possible, as long as it doesn't cause frequent page swaping on the system. I just wantto know, how can I check the memory page swapping information, like the freqency or percentage ...

thanks in advance

[Helen French]

The best tool would be GlancePlus:

# gpm

[Sandip Ghosh]

You can look at swapinfo -tm.
Look for the device Swap. In ideal condition it should be zero.

Sandip

[Vincent Fleming]

As a general rule, you should ignore the page-in metrics because most modern UNIXes will actually start programs by paging in the first page, then as it executes, demand pages in the rest of the program. I'm not sure about HP-UX, however. SVR4 does this for sure.

So, watch the page-out parameters... if this is more than just single-digits, you're paging.

Good luck!

[MANOJ SRIVASTAVA]

Hi

export DISPLAY=10.2.10.30:0.0
gpm &

or just glance in the text version ,


Manoj Srivastava

[Wodisch]

Hi Gary,

don't do that (increasing your UNIX buffer cache)!
If possible to the oppposite.
If you have the "Advanced JFS" (=Online VxFS) then actually reduce your UNIX buffer cache to at most 300-400MB, and use the special mount options "convosync=direct,mincache=direct" for the filesystems containing the Oracle data-files (but ONLY those).
The freed RAM use to increase your SGA (espcecially the "shared pool").

Just my $0.02,
Wodisch