huge swaping

[zaurak]

I have AIX 4.3.3 fix 11 instaled on R36000 model F80.
6 x CPU 600MHz 6GB RAM defined swap 8GB
On this system runing Oracle 8.0.5 and SAP 45b.
Just after startup os starts oracle and sap and statistcs
show allocated PhysicalMEM 2,5GB RAM, free size of swap is
8GB. After few days statistic show 0GB free PhysicalMEM and
4,5GB allocated swap.
I checked that application sap and oracle don't use swap.
SO I don't know what allocate swap pages.
How can I check what objects reside in swap or how can I to limit to take advantage of swap

 

[MoshiachNow]

Hi,

I observe it as a normal phenomena - AIX will consume ALL physical memory it has as soon as it needs it.

Probably swap space was consumed by the some system or other application process.Normally it should be released,if not possibly you have some "memory leak" from one of the applications (bug ?).

Anyhow - reboot will always release the swap space.

"Long live king Moshiach !"

http://www.7for70.com/

 

[Jonsie123]

What are the sizes of the sga's of the oracle instances running on the box. How many user processes on Oracle and SAP does ur box handle.
The server will have to be tuned based on these parameters using vmtune to reduce double buffering phenomenon especially while using oracle.

I had the same problem and have resolved it using the above guidelines

Cheers

 

[dblair]

Try in oracle..
alter system flush shared pool;
(Execute this 3 times).

 

[zaurak]

SGA component group Size (bytes)
Database Buffers 1.024.000.000
Fixed Size 73.540
Redo Buffers 1.056.768
Variable Size 255.787.008

About 200 users processes on SAP

 

[mrn]

Check out

http://www.softtreetech.com/monitor/

v useful for monitoring whats happening on you system as regards oracle.

--
| Mike Nixon
| Unix Admin
|
----------------------------

 

[dblair]

1.024.000.000 block buffers
This is mutlipled by the Block Buffer size (typically 8k) and is included in the shared memeory SGA at Oracle startup.
This would be 8,388,608,000,000 bytes (8 gb).
The block buffers should be reduced and this will free up memory ( CPU and virtual).

 

[Jonsie123]

Hi
Reduce ur SGA to around 60% of the real memory. Then use the following command to check and tune your memory.

/usr/kernel/samples/vmtune -p 5 -P xx

The xx values is the parameter that you will tune to reduce your swapping. Normally this parameter is around 79%. Reduce this in units of 5% and keep checking vmstat till you see no PI/PO activity. Effectively based on my experience a value around 40 to 45% seems to work good on most systems. But this is again server specific.

Also what I have observed is that a maxperm value of 20 seems to work well if you have SAP running on aix.

Cheers

 

[zaurak]

dear dblair
the above value Database Buffers 1.024.000.000 is in bytes
because the parameter in file initSID.ora is set
db_block_buffers = 125000

125000 * 8192 = 1.024.000.000