topic Re: System Memory Very High in Operating System - HP-UX

System Memory Very High

SSP_1 — Mon, 25 Oct 2004 00:47:50 GMT

System - HP Superdomes 32 Way
Os = Hp-Ux 11.11

Hi Guys ,
I am getting very high utilisation for system memory of my Superdome Server. It's consuming 3 GB out of 16 GB....I wonder what could be the reason behind it. Even if I list it using "UNIX95" syntax it shows me very less utilisation. Please help me to trace this problem.

Re: System Memory Very High

Steve Steel — Mon, 25 Oct 2004 02:09:56 GMT

Hi

It can be many things including buffer caching. What do you do with the box

What does swapinfo -at give

Look at

Memory Usage - â What is using all of the memory?â

by:eric.herberholz@hp.com

Last modified: October 18, 2004

Full document is available at external ftp site: ftp://eh:spear9@hprc.external.hp.com/memory.htm
The "Table of Contents" is available in ITRC doc id MEMORYKBAN00000975

THIS IS AN EXCELLENT SITE

Steve

Re: System Memory Very High

Geoff Wild — Mon, 25 Oct 2004 08:56:36 GMT

What is MAX_DBC_PCT set to? default is 50% - way to high for most systems today.

You want to set it so that it equals between 350 MB to 750 MB of ram.

I attached a program in c that is called memdetail - output looks like this:

# memdetail
Memory Stat total used avail %used
physical 10080.0 8405.5 1674.5 83%
active virtual 9967.9 3271.2 6696.7 33%
active real 5922.0 1893.9 4028.2 32%
memory swap 7693.5 1667.7 6025.9 22%
device swap 26528.0 9577.9 16950.1 36%

Rgds...Geoff

Re: System Memory Very High

Alzhy — Mon, 25 Oct 2004 09:07:22 GMT

You're running a SuperDome -- so you should have GlancePlus and other goodies as part of your EOE (Enterprise) or MCOE (Mission Critical) HP-UX. So, launch glanceplus and familiarize yerself with it (type ?). If you're a UNIX Vet.. you'll know how to navigate this.. specifically go to "m" or memory utlilization stats and see your memory usage.

Or under 'g' mode, hit "o" and you can sort listing of processes by RSS (memory) to see how your apps use memory...

HTH

Re: System Memory Very High

Sridhar Bhaskarla — Mon, 25 Oct 2004 12:11:36 GMT

Hi,

On 11.11, 3 GB of 16GB is not bad at all. 11.11 does better memory management than previous releases. It allots vxfs inodes dynamically so if you have bigger filesystems with a lot of files, you may find the parameter vxfs_ninode using the command

echo vxfs_ninode/D | adb -k /stand/vmunix /dev/mem

You can also find detailed usage using /usr/contrib/Q4/bin/kmeminfo command.

If you are looking at "system" memory in glance, then it doesn't include buffer cache.

-Sri

Re: System Memory Very High

RAC_1 — Mon, 25 Oct 2004 12:17:33 GMT

Where did this reading come from?? Glance would be better tool to know it.

Do you have tools - meminfo, sheminfo and kmeminfo??? On UNIX95, which system daemon/process shows "as using highest system memory??"

Anil

Re: System Memory Very High

Laurent Menase — Mon, 25 Oct 2004 16:20:57 GMT

Hi,

There is 2 possible things:
1- you had a peak utilisation, and until the system does not need that memory -memory pressure- , it stays in the arena. When there is a memory pressure, there is a garbage collection done to return a part of that memory to the system. This is normal, and is a problem only if the memory is not returned to the system if needed.
2- you have a memory leak.

If you have not crashinfo or kmeminfo, you can download PHSS_30601. It is a 11.23 patch but there is a tool named crashlite in it.
To extract it you must do:
#tar xvf PHSS_30601.depot \
PHSS_30601/KWDB-RUN/usr/contrib/ktools/bin/crashlite
# mv \
PHSS_30601/KWDB-RUN/usr/contrib/ktools/bin/crashlite \
crl.gz
# gunzip crl.gz
# ./crl -v

Look at "Buffer Cache Globals" and "Memory Globals" and "Memory Usage"
In Memory Usage look at the evolution of the arena. If you see an arena which keeps growing you probably have a memory leak;

Re: System Memory Very High

SSP_1 — Tue, 26 Oct 2004 02:21:46 GMT

HI Experts,

Thanks for all your replies.
The values derived for System Memory are using glance. My doubt is "vx_ninode" parameter , we have tuned it before 3 weeks from 0 [previous] to 50,000 [current] which is advised by HP . I can see that after this change only system meory usage is increased. Please advise.

Thanks
Shripad

Re: System Memory Very High

Alzhy — Tue, 26 Oct 2004 07:33:57 GMT

Shripad,

What exactly is the nature of your inquiry? As someone else has mentioned already - 3GB of 16GB is not HIGH a utilization.

One thing to note -- if this is a RDBMS server and youhave not modified your cache settings then you're wasiting memory -- unless of course you use Filesystems and you're not using direct IO...

HTH (and smiling)
And head wobbling side to side - ;^)

Re: System Memory Very High

Geoff Wild — Tue, 26 Oct 2004 07:51:53 GMT

vx_ninode - interesting - did you run a System Health Check?

I just did - and received the same issue...

Here's the strange thing - there seems to be a discrepency with which it should be tuned to:

The SHC report says I should tune to 8192, but in the following doc, it states that vx_ninode be set to more than that of nfile:

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/5990-6728/5990-6728_top.html&con=/hpux/onlinedocs/5990-6728/00/00/76-con.html&toc=/hpux/onlinedocs/5990-6728/00/00/76-toc.html&searchterms=vx_ninode&queryid=20041005-084805

My system is a SAP system - and nfile is set to 189100

I also attached the section on vx_ninode from my SHC report.

Needless to say, I'm not to sure if I should change or not.

In your case, you say you noticed an increase in memory - doesn't make sense from this parameter - as with 16GB of ram, 128000 would have been set and you have reduced to 50000...

Rgds...Geoff