shmmax value

[Shahul]

Hi,

Just for the reason of upgrading physical memory, you don't need to increase Shmmax. Check with you application vendor what should be you shmmax. When you upgrade your physical memory, the good prachtice is to alter your swap and dump. Again it is not a hard and fast rule, it's all depending on your requirement.

Good Luck
Shahul

[Ganesan R]

Hi Amit,

I didn't noticed that your OS version is 11.0. I though it is higher version. In all higher versions, shmmax can be increased dynamically.

[Amit Manna_5]

hi
Can we increase the kernel paramter in single user mode. If yes please let me know the process.

[Hein van den Heuvel]

>> Can we increase the kernel paramter in single user mode. If yes please let me know the process.

Noop.
That's why it is called 'kernel' param.
One setting for all.

Hein.

[Sharma Sanjeev]

Hi Amit

You can not change/increase in Single User mode :-)

Regards
Sanjeev

[Hein van den Heuvel]

oh wait, I guess I was reading the last question wrong (shouldn't visit forums before first coffee). I read it as 'for a single user', but surely it was 'with the system in single user mode'.
Yes, you can do that. But you can just set the parameters to chance (kctune) on the running system, for the next reboot.

Hein.

[Avinash20]

On a running server

# kctune shmnax=

<< Above could be run without a reboot>

When you are ready with the downtime

# kmupdate
> Reboot the server

All the best

[Doug O'Leary]

Wow; what an entertainingly contradictory thread!

First, lets verify the environment:

It's an 11.00 system on which he's upgrading ram for 4 gigs to 6 gigs.


A couple of the more entertainingly incorrect answers:

1. kctune is 11.23 and 11.31; not 11.00. kmtune is the right command.

2. swap does not have to be 2x ram. That is archaic thinking - although, in this particular case, since it's an archaic operating system with an archaic amount of ram, the 2x ram may be right.

The right answer for the shmmax parameter is it doesn't have to be upgraded and you should check with the vendor. If you're running oracle, it probably should be. *That* being said, you're also probably running an antiquated version of oracle. Versions prior to 8.1.6 (I believe?) couldn't access more than 4 gigs of shared memory in one swell foop anyway, so updating the shmmax beyond that point doesn't get you much - and, may, in fact, prevent oracle from starting.

Should you decide to do the kernel upgrade, it will require a reboot. If you ever upgrade to 11.23 there are significantly more dynamic kernel parameters. Yet more in 11.31. Those two OSes make kernel updates a breeze, though. Run the appropriate kctune commands, then run kctune -D to find out if you need a reboot.

Here's a checklist for command line kernel creation that I always use:

http://www.olearycomputers.com/ll/hpkernel.html

This applies to 11.11 and prior; as I said, the 11.23/11.31 kernel process is so easy it doesn't require a checklist.

Hope that helps.

Doug O'Leary

[Avinash20]

"kctune in 11.11"

Oops.. Need good sleep before replying to number of thread.
Will make a habit of reading the complete thread bfor answering.

Thanks Doug for catching it ..

[Dennis Handly]

>Avinash: "kctune in 11.11" Need good sleep before replying to number of thread.

There is nothing wrong with mentioning kctune(1m) provided you put the right marketing spin on it. :-)
I.e. You can use kctune on 11.23 and shmmax is dynamic tunable so you don't have to reboot.