Why is it important to have xms and xmx value as same?

Rahul Aich [Nagra]

Hi Guys

I remember someone tell me to set xmx and xms value as same. i.e. xmx=xms=2048.

Can anyone please tell me why is this important. We run JIRA as a service on windows, JIRA 6.1,1200 users, 120K issues

My current configurations are Xmx =2048 Xms=512 Max Perm Size=384.

Will updating my Xms=Xmx improve performance?

Rahul

Andy Heinzer

According to the Oracle JVM Tuning guide: https://docs.oracle.com/cd/E40972_01/doc.70/e40973/cnf_jvmgc.htm#autoId2

setting the xms to be the same as the xmx will prevent pauses caused by heap expansion.  In turn it can help prevent performance issues within JIRA while waiting for JAVA to deal with memory allocation changes.