Hi!
I have a hpux11.23 server, running Oracle and several instances of a
propriety, memory-consuming C application.
I experience problems in memory utilization.

There is 8GB of RAM installed in it.

swap report in Glance shows:
avail: 16GB, Resv: 9.3GB, Used: 3.1GB, Resvd Util: 58%
with following swap devices
/dev/vg00/lvol2  - avail: 8GB, Used 0MB, type: device, pri: 1
pseudo-swap   - avail: 8GB, Used 3.1GB, type: memory, pri: -1

which I understand as a lot of free virtual memory (16 - 3.1 = 12.9
[GB]).

But memory report says that:
Total VM :   8.1gb   Sys Mem  :   1.9gb   User Mem:   4.4gb   Phys
Mem :   8.0gb
Active VM:   4.0gb   Buf Cache:   1.6gb   Free Mem:   103mb
FileCache:      n

What means I have almost no free memory.

How can I increase free memory by tuning up the system? Why Total VM
doesn't show 16 GB while swap avail says its 16 GB?

I cannot simply add more memory or reduce number of applications.

thanks for any advice.

regards, Julian Kania

On Thu, 25 Oct 2007 04:46:51 -0700, "julian.kania@gmail.com"
<julian.kania@gmail.com> wrote:

>Hi!
>I have a hpux11.23 server, running Oracle and several instances of a
>propriety, memory-consuming C application.
>I experience problems in memory utilization.
>
>There is 8GB of RAM installed in it.
>
>swap report in Glance shows:
>avail: 16GB, Resv: 9.3GB, Used: 3.1GB, Resvd Util: 58%
>with following swap devices
>/dev/vg00/lvol2  - avail: 8GB, Used 0MB, type: device, pri: 1
>pseudo-swap   - avail: 8GB, Used 3.1GB, type: memory, pri: -1
>
>which I understand as a lot of free virtual memory (16 - 3.1 = 12.9
>[GB]).
>
>But memory report says that:
>Total VM :   8.1gb   Sys Mem  :   1.9gb   User Mem:   4.4gb   Phys
>Mem :   8.0gb
>Active VM:   4.0gb   Buf Cache:   1.6gb   Free Mem:   103mb
>FileCache:      n
>
>What means I have almost no free memory.
>
>How can I increase free memory by tuning up the system? Why Total VM
>doesn't show 16 GB while swap avail says its 16 GB?
>
>I cannot simply add more memory or reduce number of applications.
>
>thanks for any advice.
>
>regards, Julian Kania

You can likely free memory currently used by the filesystem buffer
cache - maybe a half-Gb or more depending upon how you're utilizing
the buffer cache.

Is your DB in filesystems? If not then you're not likely to need much
of a buffer cache. If it is, then with OnlineJFS you could mount
certain db filesystems to bypass the filesystem buffer cache (ask
Oracle about that) and then make use of the database buffer cache
(that you might even be able to increase in size after freeing memory
from the buffer cache -databases generally make good use of the memory
they're given).

The system memory usage is on the high side. Ask the HP Response
Center to take a look at kmeminfo output and see how the system memory
is being used. Perhaps a half-Gb to free there??

Don't worry about the 16-Gb VM number, or the swapinfo output until
your PCT Used value on the total line of swapinfo -tam approaches 90
or 100%. Keep an eye on the PCT Used values on the Dev line(s) - but
if memory gets paged out that's not necessarily a bad thing - so long
as it's little used memory.

The 4 Gb Active VM means that half your physical memory is getting a
workout.

Regards,
Eric Stahl

> >I have a hpux11.23 server, running Oracle and several instances of a
> >propriety, memory-consuming C application.
> >I experience problems in memory utilization.
> > [...]

> You can likely free memory currently used by the filesystem buffer
> cache
Yes, this caused in freeing about 600MB of memory by the price of
higher disc utilisation, but this is OK.
Thanks for the help.

regards,
Julian Kania