topic Re: Filesystem buffer cache in Operating System - HP-UX

Filesystem buffer cache

Eric SAUBIGNAC — Mon, 19 Nov 2007 11:43:18 GMT

Hi every body,

until HP-UX 11iv1 i was looking at filesystem buffer cache with the following command :

echo "bufpages/D" | /usr/bin/adb /stand/vmunix /dev/kmem

This way of getting the value doesn't work since HP-UX 11iv2.

Does anyone know the proper way to do it ?

Thanks in advance

Eric

Re: Filesystem buffer cache

A. Clay Stephenson — Mon, 19 Nov 2007 12:05:27 GMT

Bufpages is no longer defined at 11iv2 and up and your method would only have meaning in 11iv1 in that case of a static buffer cache.

change your "bufpages" to "dbc_min_pct" and "dbc_max_pct" and you will have the values that the buffer cache fluctuates between.

Re: Filesystem buffer cache

rajdev — Mon, 19 Nov 2007 12:07:05 GMT

Hi Eric,

I use 11.23 (PA) and it seems to work ...
# echo "bufpages/D" |adb /stand/vmunix /dev/kmem
bufpages:
bufpages: 69622

try this , use -o or -n ( compatibility or normal mode )

#echo "bufpages/D" | adb -o /stand/vmunix /dev/kmem

Regards,
RD

Re: Filesystem buffer cache

Eric SAUBIGNAC — Mon, 19 Nov 2007 12:19:56 GMT

Clay, that's because i use dbc_min_pct and dbc_max_pct as kernel parameters instead of bufpages that i would like to know at a glance how much memory is in used by FS buffer cache.

Rajdev, i test your syntaxe ... as soon as i get an HP-UX box

Re: Filesystem buffer cache

Geoff Wild — Mon, 19 Nov 2007 12:36:45 GMT

If you want usage, then use:

kcusage

kcusage |grep dbc_max_pct

In 11.31:

kcusage |grep filecache_max

Rgds...Geoff

Re: Filesystem buffer cache

Eric SAUBIGNAC — Mon, 19 Nov 2007 13:06:55 GMT

Well, Rajdev, finally I got an HP-UX box more quickly than i thought. So, thanks, the "-o" option is the definitively answer.

Geoff, i didn't know i could have the current value of the data buffer cache with "kcusage dbc_max_pct". Thanks for the information ... but the returned value is just an integer percentage which is less accurate than bufpages.

Thanks every body

Eric

Re: Filesystem buffer cache

Eric SAUBIGNAC — Mon, 19 Nov 2007 13:09:47 GMT

EOF