topic Re: memory problem in Operating System - HP-UX

memory problem

sachit patil — Tue, 12 Sep 2006 07:29:44 GMT

Hello all ,
I have d220 server installed 256 mb memory and swap size is 512 mb .I installed 1GB memory that make server slow .Server is showing more load in top than its before .how can that load should be minimised .
regards
sachit pail

Re: memory problem

spex — Tue, 12 Sep 2006 07:37:40 GMT

Hi Sachit,

A dynamic OS buffer cache will grow to use all available memory. This process incurs CPU overhead. You may need to switch to a fixed OS buffer cache.

PCS

Re: memory problem

sachit patil — Tue, 12 Sep 2006 07:40:40 GMT

But how it can be done .pls give me details
sachit

Re: memory problem

spex — Tue, 12 Sep 2006 07:50:39 GMT

You should post your question in the Linux or Windows XP forum, depending on the OS you are running.

Re: memory problem

Jeff Schussele — Tue, 12 Sep 2006 07:52:58 GMT

Slow doing what?
If it's booting that's entirely normal.
It take longer to perform POST on more memory.

Rgds,
Jeff

Re: memory problem

James R. Ferguson — Tue, 12 Sep 2006 07:58:40 GMT

Hi Sachit:

What process(es) are consuming the processor?

Are you swapping? Use 'vmstat' and look for page-outs.

Do you have a large buffer cache set? Look at the values for 'dbc_max_pct' and 'dbc_min_pct'. Is 'syncer' one of the top processes?

You need to post more information. The release, and 'swapinfo -tam' and something about your application environment --- database?

Regards!

...JRF...

Re: memory problem

sachit patil — Tue, 12 Sep 2006 08:00:07 GMT

Hi all
I am working on 10.20 os.I boots normally .but applications are going slow .
sachit

Re: memory problem

sachit patil — Tue, 12 Sep 2006 08:02:48 GMT

hi

Syncer daemon is on top .
sachit

Re: memory problem

Jaime Bolanos Rojas. — Tue, 12 Sep 2006 08:04:32 GMT

Sachit,

Chances are our questions to you might are bit difficult at the moment, please take some time to read this document, it will make you understand memory on hp-ux better and then be able to answer our questions or even find the solution to your problem.

ftp://eh:spear9@hprc.external.hp.com/memory.htm

Regards,

Jaime.

Re: memory problem

Prasanth B — Tue, 12 Sep 2006 08:09:14 GMT

Hi

First of all you will need to add more swap space to make use of the additional memory. Make it 1GB minimum. Also, by defaukt the size of buffer cache is 50%, change the kernel parameter max_dbc_pct to 10 and min_dbc_pct to 5 to modify buffer cache.
-PB

Re: memory problem

sachit patil — Tue, 12 Sep 2006 08:13:46 GMT

hi
I stop the syncer .load is normal .
thanks
sachit

Re: memory problem

Victor BERRIDGE — Tue, 12 Sep 2006 08:25:26 GMT

Stoping syncer isnt good...

What are you running on this box?
Start by adding enough device swap then be sure that swapmem_on is at 0.
I have a D220 10.20 running oracle 7.2.3
Here are the tunable parameter values so you can use as ref (Yes this box has 1GB RAM...)
STRMSGSZ 65535
dbc_max_pct 25
max_thread_proc 128
maxfiles 256
maxfiles_lim 1280
maxswapchunks 2048
maxuprc 100
maxusers 128
maxvgs 20
msgmax 32768
msgmnb 65535
msgseg 32560
msgssz 128
msgtql 8140
nfile 2000
nflocks (200+(4*NPTY))
npty 72
nstrpty 60
semmni 400
semmns 512
semmnu 500
semume 500
shmmax 83886080
shmmni 1024
swapmem_on 0

All the best
Victor

Re: memory problem

James R. Ferguson — Tue, 12 Sep 2006 08:30:12 GMT

Hi Sachit:

The 'syncer' daemon is responsible for managing the Unix buffer cache. Look at '/stand/system' for your values of 'dbc_max_pct', 'dbc_min_pct', 'bufpages' and 'nbuf'. I suspect that the last two parameters have a value of zero thus enabling the values of 'dbc_max|min_pct' to control the size of the buffer cache. You probably need to reduce the size of the buffer cache so that when 'syncer' runs it has less work (modified buffers) to flush.

Regards!

...JRF...