topic Re: Vhand issue in Operating System - HP-UX

Vhand issue

Ani Abraham — Mon, 15 May 2006 11:25:19 GMT

we are having
RP1 server with HP Unix V.11.11 & Oracle 8.1.7 loaded, In which vhand
Process is consuming a lot of CPU usage, Sometimes two Vhand processes
running at high CPU %. This is happening at low load and as well as high
load also. As vhand is taking all the system resource, it is making all
other applications very slow, thus effecting the performance of the database
server. Please Help.

Re: Vhand issue

Patrick Wallek — Mon, 15 May 2006 11:37:48 GMT

If vhand is taking up a lot of CPU it is generally because of memory pressure and vhand is having to page out.

Check your 'swapinfo -tam' output to see what your swap situation is.

Re: Vhand issue

Prashant Zanwar_4 — Mon, 15 May 2006 11:52:38 GMT

You are swapping a lot I believe.

try working out memory statistics through

UNIX95 command line and also you can use vmstat..

Prashant

Re: Vhand issue

Steven E. Protter — Mon, 15 May 2006 11:56:18 GMT

Shalom Ani,

I think that your system is paging processes in and out of swap heavily and you would benefit from more memory.

vmstat will help you see this issue.

http://www.hpux.ws/system.perf.sh

SEP

Re: Vhand issue

Sameer_Nirmal — Mon, 15 May 2006 15:09:44 GMT

Hi Ani,

Check for following as well besides already above.

dbc_min_pct & dbc_max_pct

Because of memory pressure, vhand might need to stale the pages from buffer to cater the memory pressure.

Are you using Filesystem based or Raw device based Oracle application?

Whats the patch status of the system?

Re: Vhand issue

philemon_1 — Tue, 16 May 2006 05:11:51 GMT

do we have to change any kernal perameters like lotsfree, minfree & desfree. And also we are having 4GB ram.

root@rp1 />swapinfo -tam
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 8192 1182 7010 14% 0 - 1 /dev/vg00/lvol2
reserve - 3094 -3094
memory 3087 1013 2074 33%
total 11279 5289 5990 47% - 0 -

root@rp1 />vmstat
procs memory page
faults cpu
r b w avm free re at pi po fr de sr in
sy cs us sy id
1 3 15 281987 3330 72 0 3 3 0 0 61 1459
14576 2780 34 5 61

Re: Vhand issue

Ani Abraham — Tue, 16 May 2006 15:42:48 GMT

Hi experts

thanks for responding.do i have to change any kernel parameters like desfree,minfree or lotsfree?.i checked both swapinfo and vmstat.where can i get detailed information regarding patches??

thanks a lot