topic Re: Memory Issue in Operating System - HP-UX

Memory Issue

sujeet joshi — Tue, 16 Jan 2007 08:29:07 GMT

Hi,

One of our HP9000 server RP4440 giving memory problem.DP cell manager is installed and oracle 9.2 and SAP Application installed on this server.Server is with 2 CPU and 2GB RAM.

when I issue a command swapinfo it shows PCT USED 99 % and stops for command access.

Can any one help us in this issue?

Is there any memory upgradation is required?

Sujeet

Re: Memory Issue

Safarali — Tue, 16 Jan 2007 08:36:01 GMT

you can solve this issue by creating additional swap (file system swap) on your server

Regards
Safar

Re: Memory Issue

sujeet joshi — Tue, 16 Jan 2007 08:41:12 GMT

Thanks for reply.

But my device swap is showing only 9 %.

shall i go for memory upgrade?

Please advice.

Re: Memory Issue

Jaime Bolanos Rojas. — Tue, 16 Jan 2007 08:54:33 GMT

sujeet,

what do you have in the total line?

If that value is close to 100 then there is the problem.

Do you have pseudo swap enable on the machine.

Please post the output for swapinfo -tam

Depending on the output, we will be able to know if you need more memory or if it's something else.

Regards,

Jaime.

Re: Memory Issue

Brad Smithberger — Tue, 16 Jan 2007 08:55:39 GMT

Hi Sujeet

Consider upgrading memory. 2GB is not very much considering all you have on your server.

HPUX 750MB to 1G
DP 512MB + 40MB per backup session
Oracle 512MB+
SAP 512MB+
====================
> 2GB

Brad

Re: Memory Issue

Steven E. Protter — Tue, 16 Jan 2007 09:09:14 GMT

Shalom,

Please post the results of this command:

swapinfo -tam

This will tell us how much system memory you have and how much swap.

I talked with oracle two years ago while planning a memory upgrade and they said many customers found 4 GB a good performance point for memory.

However its been two years since then and we went with 8 GB to support a database server/app server on one piece of hardware environment.

You may next need to look at your oracle sga and kernel to see what impact settings there have.

kmtune or kctune will display kernel settings depending on your OS.

The 9% statement below is a bit confusing. What is memory usage and swap usage.

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

SEP

Re: Memory Issue

sujeet joshi — Tue, 16 Jan 2007 09:50:18 GMT

Thanks for reply.

Here is the O/P of swapinfo.

Thanks

Sujeet

Re: Memory Issue

Patrick Wallek — Tue, 16 Jan 2007 09:58:30 GMT

I would say that you DEFINITELY need more RAM. As said earlier, 2GB is not a whole lot for modern machines, especially with HP-UX requirements.

I would add at least another 2GB, maybe 4GB.

You can see how badly you are paging out by doing a :

# vmstat 5 12

In this output look at the 'po' column. This shows the page out activity. If the number are above 0, then you have some po activity. If the numbers are into the double-digit range then you moderate to heavy po activity. If the numbers are above 100, then you have heavy po activity and REALLY need more RAM.

Re: Memory Issue

Jaime Bolanos Rojas. — Tue, 16 Jan 2007 10:38:17 GMT

Sujeet,

As I said before, if you total line is close to 100% then you are in troubles, agreed with the above answers, buy more memory for the machine. As you add more memory to the machine, do not forget to add proporcional amount of dev swap to the system as well.

Regards,

Jaime.

Re: Memory Issue

Bill Hassell — Tue, 16 Jan 2007 18:44:27 GMT

Your system is being strangled by lack of RAM. I am very surprised that you even got SAP and Oracle loaded... 4Gb is probably too small unless you do not have a lot of activity on the system. A typical SAP system will need a couple of Gb just for shared memory and 6Gb to 8Gb for normal operations. A really busy system may need 12Gb to 24Gb. vmstat will tell you how bad it is: Look at po (page out) and if you see 2 digits or higher (greater than 10-20) during busy periods, everyone will see a slow system. Even a login will be very sluggish when po is greater than 40-60.

Note that 2 CPUs may also be a problem in the future. If you add more memory, you will see CPU time go up (and disk I/O drop) as more things are done in memory.