error in alert log.

[TTr]

> reserve - 16002 -16002

It looks like your address space may have been exhausted.
There may not be active disk swapping which means that you will not have i/o issues but almost all your swap space is reserved by the running processes.

You need to add more swap space.

After you add more swap space, more processes will run which means that the server most likely will swap to disk actively and the performance will decrease tremendously. So adding more memory would be a good idea.

[AnthonySN]

TTr> but almost all your swap space is reserved by the running processes.

which processes you mean, which is that process which requires 16GB swap reservation.

[TTr]

> which processes you mean, which is that process which requires 16GB swap reservation

All of the running processes combined.

In the meantime you can look in the running processes and see if you can clean up any of them or turn off any unnecessary services.

[AnthonySN]

the same application was running on an old server with just 5 GB ram and hardly there were any such memory problem, with 16 GB ram it would be not justifiable to ask for more physical memory.

[AnthonySN]

TTr>>
> reserve - 16002 -16002
It looks like your address space may have been exhausted.

may you pls shed some light on the above.
is there any way to reduce the reserve.
how can the d/b start using swap space if short of memory. and what is address space ?

[Dennis Handly · Accepted solution]

>is there any way to reduce the reserve?

Only by running fewer processes, or smaller/fewer shared memory segments.

>how can the db start using swap space if short of memory.

You have to have more unreserved device swap.

>and what is address space?

In this case, I assume TTr really meant reserved device swap used up all of the device swap.

[AnthonySN]

> Only by running fewer processes, or smaller/fewer shared memory segments.

how can we reduce those processes?
we have checked the services running and they are bare minimum, its a cluster and ora10g running on it, whenever the mumber of sessions reaches 1600+ the memory utilization touches 100%.
and why is that swap utilization shows only 3% used.
we need strong reasons to justify the additional memory needed.

[Dennis Handly]

>the same application was running on an old server with just 5 GB ram and hardly there were any such memory problem, with 16 GB ram

What does "swapinfo -tam" show for both machines?
Did you configure your Oracle SGA too large on your new machine?

[Dennis Handly]

>how can we reduce those processes?

By killing them or not starting them. Or setting some configuration value to not do so many.

>number of sessions reaches 1600+ the memory utilization touches 100%.

Less sessions?

>why is that swap utilization shows only 3% used.

You have reserved that space for growth. If you don't want to grow, you shouldn't reserve so much.

>we need strong reasons to justify the additional memory needed.

You can just add more device swap first and check your performance.

[AnthonySN]

the application is now migrated to this new system so i cant get the swapinfo -tam output now.

sga is 2.5 gb