HPUX 10.20: Memory Utililization 100%

[LG Porter]

I have a HP K570 Server with HPUX 10.20 OS running Informix 7.31 DB engine. The memory utililization us showing 100%. What processes or kernel parameter should I check that are assoicated with Informix? Is there any known problems associated with HPUX 10.20 and this version of Informix 7.31? Is there any trouble-shooting information available?

[Anil C. Sedha · Accepted solution]

Hi,

First of all run "top" command and see what processes are running and if they are taking a high CPU and memory usage.

If you have glanceplus installed then run "gpm" on your system after exporting your display settings and you should be able to drill down to the process name which is causing problems to you.

You should be able to get the process name through these steps.

Regards,
Anil (Don't forget to assign points if answers are valuable to you)

[Patrick Wallek]

Another thing to check is your dbc_maxpct setting. If it is at the default of 50, that can probably be changed. The value you change it too depends on the amount of memory your system has.

As said above, run top or glance/gpm and see what processes are using up your memory.

Also, more information about your system would help, like how much memory do you have installed?

[Martin Johnson]

Memory utilization of 100% is not necessarily bad. You need to check paging/swaping rates. If these rates are low or zero, then there shouldn't be a problem. If they are high, you'll need to do some tuning or buy more memory.

Use glance to look at paging/swaping rates. Glance can also tell you how your memory is being used, sys, user, cache.

You may want to talk to your DBAs on how Informix is using the memory allocated to it.

HTH
Marty

[Ted Ellis_2]

we have had cases where our Sybase processes failed to stop or crashed in a less than pretty fashion.. the result was that the shared memory segment did not get released and when the sybase server was restarted it gobbled up another chunk of memory. You may want to check and see of you have any orphaned memory segments....

ipcs -tam will report the shared memory segments... should see a bunch... the larger ones will be the ones to look at. If you find a memory segment for which the process should not be running.... you can use ipcrm (but please make sure the segment is orphaned before you touch it)...

[Bill Hassell]

To sort all the processes based on memory usage:

UNIX95= ps -e -o vsz,ruser,pid,args | sort -rn | more

HP-UX is a virtual memory system so using 100% is fine unless the system is severely paging (swapping). vmstat will tell you that in the po column. If it is paging more than 2 digits for long periods, you are severely short of RAM. For 10.20, the maximum RAM is 3.75Gb.

[Matt Walker_1]

You can also check your informix configuration file (onconfig). It is possible that it is configured to initialize a TON of memory when it starts up. If I was you, I would take
a look at the shared memory configuration within the informix onconfig file.