swap space limit in AIX 5.2

[Ogzilal]

Hi All,

I have read about a 2GB limiation for swap space with AIX 4.3 in the following white paper :

http://www.ibm.com/servers/aix/products/aixos/whitepapers/pagingspace.pdf

I have a box with AIX 5.2 8GB RAM (hardware 64bit; Kernel 32bits)

My questions :

Is the 2GB limitation still applies to AIX 5.2 ?
If yes, may the swap space be greater than RAM size ?

In advance many thanks.

 

[RMGBELGIUM]

strictly taken , 1 Gb of swap should cover the needs of your server, but if you really lack the memory, then you can increase it.You are not limited to having 2 Gb of swap in AIX5.2.On our testmachine we have about 6 Gb swap, running on AIX5.2.
We divided the swap into 6 files of 1 Gb,evenly divided over 2 different disks.

rgds,


R.

 

[Ogzilal]

Hi,

Thanks RMGBELGIUM for your reply, for instance the box goes OK with 1GB swap space. I just want this information to complete our documentation about swap space.

 

[RMGBELGIUM]

you must allways take in consideration the applications that the machine is running.Some apps require more swap then others, and the 1 Gb will certainly NOT cover that( eg oracle DB or IAS server )

rgds,

R.

 

[hfaix]

it really depends, I run a oracle db server on a 5.3 system with 16GB of RAM and 2GB of swap/paging space. No problems.

I also run some 5.1 machines with 24GB of RAM and 32GB of swap/paging space. This was under the the recommendation of an oracle consultant.

 

[Ogzilal]

Thanks hfaix,

This answers my second question.

Our box is running an oracle 9.2.0 instance and some java methods from Documentum software. For instance, it's OK and is rebooted monthly.
Swap space is used upon 20% reported by "lsps -s" command.
But sometimes when we shutdown oracle for cold backup and no other process is running but only the OS, lsps still reports about 10% used.

How can one explain this used swap space when no activity is observed on the box.