swap space question 11.23v2 IA64

[Chris Fadrowski]

We have been running our Itanium system now for serveral months. All of a sudden our swap space is pegged today. Nothing out of the ordinary is going on. Can anyone suggest how to trouble shoot this problem..

I found this while viewing glance, and users are experiencing some problems.

CPU 2%
Disk 4%
swap 100%
Memory 100%

[RAC_1]

How much swap has been configured?? How much RAM do you have?? Also as, you see your memory utilization is 100%, you started swapping. Also swapping reached 100% because, processes kept starting.

What are your settings for dbc_max_pct and dbc_min_pct?? In a nutshell, there are too many user processes running on your system.

Anil

[Steven E. Protter · Accepted solution]

You may have triggered a fault that needs to be patched.

I'd take a look in the patch database and maybe collect some performance data over time with the scripts I attach to pinpoint the problem.

These scripts will increase resource usage.

Check glance shared memory information too.

SEP

[Chris Fadrowski]

Have 8 gb of RAM, and 4gb of swap..

i did a ps-elf | sort -k10.1rn | head

and it's showing me its ora_lgwriter..


DB_max_pct is 25
db_min_pct is 5

[Kent Ostby]

Well, your swap space is well below the amount HP recommends which is 2 x RAM at a minimum.

What is probably happening is that RAM is full and so you are having to try to use SWAP and you just don't have enough (since much of it is used as "reserve" space).

So I would do two things:

1) Increase your SWAP space

2) Check to see if anything is grabbing a lot of CPU / memory via glace.

If you don't have glance, you can use this quickie "ps" command to find what is grabbing CPU at least:

ps -ef | cut -c46-80 | sort -nr

Best regards,

Oz

[Ted Buis]

With up to 2GB (25% of 8GB of RAM) possibly in use by the buffer cache, I would consider reducing the max buffer cache to 1GB or less. While buffer cache is dynamic, it doesn't get reduced instantly if there is spikes in memory demand. This should help eliminate some page outs. You can buy more RAM, increase swap space (recommended) or both. I assume Pseudo-swap is enabled. Naturally, you need to check for the possiblity of a memory leak in your application.