Full GC on java server nodes

[Former Member]

Hi guys,

My portal system is on SAP NW 7.0 EHP2 and backend on ECC 6 EHP6.  Recently, on the portal system I'm getting lot of Full GCs and concurrent mode failure. I have two server nodes and heap size set to 3gb for both (It was 2gb initially). When the Full GCs and concurrent mode failure are occurring, users are not able to work on the portal application and it is timing out. It is only becoming operational again long after a heap dump occurs or I restart the instance manually.  Please suggest how I can resolve this issue.

Additional info: The portal is a Tax Officer Portal used to view, input and amend tax returns. Since the portal is java stack, my ECC system uses this java stack for ADS (z-reports displayed in PDF).

So the issue is that I'm unable to know what is causing the frequent Full GC situation and the OOM heap dump. I tried to analyze using Memory Analyzer but it's not clear enough. Please advise.

Regards.

[Former Member]

Hi Suraj,

Do you have Wily Introscope configured?  This is the best tool to see the memory usage and growth and you can drill down into the program causing the memory usage.

Regards,

Graham

[bxiv]

As @Graham suggested you need a Java Heap tool (Wily while free to use, take time to setup on a Solution Manager system and should be setup prior to issues on systems).

As a test you could raise 1 of the servers to 4 or 6 gigs of heap and see if the amount of time it takes for the GC to start occurring is about the same time or less; as this could help with narrowing down if it is a number of users connecting to the system or a bad transport went through and changed something.

Another option if you do have Solution Manager setup, is to try a E2E trace under the RCA tab as this might tell you where/what business processes are doing to the systems.