Swapping

UNIX Solaris
1

Hi Guys

I am using SPARC-T4 (chipid 0, clock 2998 MHz), SunOS 5.10 Generic_150400-38 sun4v.

How do I see if the server was doing some swapping like yesterday?

I had a java application error with java.lang.OutOfMemoryError, now I want to check if the server was not doing some swapping at that time.

Thanks in advance

2

You need some kind of monitoring in place to go back in time and see what happens... For example something like sar .

Collecting System Activity Data Automatically (sar) - Oracle Solaris Administration: Common Tasks

3

You might have a look in the sar output if your system uses sar - which may or may not be the case.

Otherwise, you might have some performance monitoring tool running and might find information in its output.

Otherwise, i suppose you are out of luck: you can see the current swapping - quite detailedly so - in the vmstat output, but the figures from yesterday are not there (and to my knowledge anywhere saved). In this case you might set up something - log vmstat to a file, start sar , etc.. - and wait until the problem occurs again.

I hope this helps.

bakunin

4

Also, check out system logs.

If the memory pressure was extra high, you should messages from various services like :
[some service] : Unable to fork, not enough space ....

Are you running your java program inside application servers (websphere, glashfish, tomcat etc.) or from command line ?
Perhaps a JVM -xmx increase could help in either case ?
What is your app / program doing ?

I doubt you ran out of memory on t4 bare metal, you run out of memory inside your JVM.

5

You can quickly monitor it in a terminal with the vmstat command

vmstat 2

pi and po columns are page-in and page-out, that is nearly identical with swapping

vmstat -S 2

displays the exact figures in si and so columns (swap-in and swap-out).
Note that the first line in the vmstat output is the average since system boot.
Every subsequent line is the current activity (average of the 2 seconds interval).