[jboss-user] [Installation, Configuration & DEPLOYMENT] - startup jvm memory config suggestions

jschneider do-not-reply at jboss.com
Mon Mar 10 16:30:00 EDT 2008


Version: 4.0.5 GA
OS: Linux Red Hat Enterprise

We started getting PermGen errors on one of our servers. Before digging in to understand what this meant, my knee-jerk reaction was to just add more memory. We increased from 4GB to 8GB.

After digging in to PermGen more (reading until my eyes glossed over), I found the PermSize/MaxPermSize. After upgrading the memory, I tried changing the jvm config options to take advantage of the new memory. JBoss is about all that is running on that server so I'd like to give it as much memory as possible. I figured I could up -Xmx to 6GB and then up MaxPermSize to 256m, but I got startup errors when I did that. "not enough heap space" (and some other one that I can't remember). Here are the java-opts that I have now:

-Dprogram.name=run.sh -server 
-Xms2560m -Xmx2560m -Dsun.rmi.dgc.client.gcInterval=1800000 -Dsun.rmi.dgc.server.gcInterval=1800000 -XX:MaxPermSize=128m -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC

While I'm not sure it's related, our users were complaining of performance issues today. With the garbage collection enabled as above, we got this (first entry and most recent):

================================================================================
{Heap before gc invocations=1:
 PSYoungGen      total 254912K, used 56837K [0x9f9f0000, 0xb1660000, 0xb1660000)
  eden space 218560K, 26% used [0x9f9f0000,0xa31717d8,0xacf60000)
  from space 36352K, 0% used [0xaf2e0000,0xaf2e0000,0xb1660000)
  to   space 36352K, 0% used [0xacf60000,0xacf60000,0xaf2e0000)
 PSOldGen        total 2330176K, used 0K [0x11660000, 0x9f9f0000, 0x9f9f0000)
  object space 2330176K, 0% used [0x11660000,0x11660000,0x9f9f0000)
 PSPermGen       total 16384K, used 8080K [0x09660000, 0x0a660000, 0x11660000)
  object space 16384K, 49% used [0x09660000,0x09e44068,0x0a660000)
2.687: [GC [PSYoungGen: 56837K->3028K(254912K)] 56837K->3028K(2585088K), 0.01156
90 secs]
Heap after gc invocations=1:
 PSYoungGen      total 254912K, used 3028K [0x9f9f0000, 0xb1660000, 0xb1660000)
  eden space 218560K, 0% used [0x9f9f0000,0x9f9f0000,0xacf60000)
  from space 36352K, 8% used [0xacf60000,0xad2553c8,0xaf2e0000)
  to   space 36352K, 0% used [0xaf2e0000,0xaf2e0000,0xb1660000)
 PSOldGen        total 2330176K, used 0K [0x11660000, 0x9f9f0000, 0x9f9f0000)
  object space 2330176K, 0% used [0x11660000,0x11660000,0x9f9f0000)
 PSPermGen       total 16384K, used 8080K [0x09660000, 0x0a660000, 0x11660000)
  object space 16384K, 49% used [0x09660000,0x09e44068,0x0a660000)
}

================================================================================
{Heap before gc invocations=559:
 PSYoungGen      total 179072K, used 175247K [0x9f9f0000, 0xaf100000, 0xb1660000
)
  eden space 174784K, 100% used [0x9f9f0000,0xaa4a0000,0xaa4a0000)
  from space 4288K, 10% used [0xaecd0000,0xaed43d20,0xaf100000)
  to   space 39104K, 0% used [0xaa4a0000,0xaa4a0000,0xacad0000)
 PSOldGen        total 2330176K, used 214697K [0x11660000, 0x9f9f0000, 0x9f9f000
0)
  object space 2330176K, 9% used [0x11660000,0x1e80a770,0x9f9f0000)
 PSPermGen       total 68736K, used 64198K [0x09660000, 0x0d980000, 0x11660000)
  object space 68736K, 93% used [0x09660000,0x0d5118c0,0x0d980000)
39479.614: [GC [PSYoungGen: 175247K->352K(174592K)] 389945K->215333K(2504768K),
0.0041540 secs]
Heap after gc invocations=559:
 PSYoungGen      total 174592K, used 352K [0x9f9f0000, 0xaed70000, 0xb1660000)
  eden space 174208K, 0% used [0x9f9f0000,0x9f9f0000,0xaa410000)
  from space 384K, 91% used [0xaa4a0000,0xaa4f8020,0xaa500000)
  to   space 37568K, 0% used [0xac8c0000,0xac8c0000,0xaed70000)
 PSOldGen        total 2330176K, used 214981K [0x11660000, 0x9f9f0000, 0x9f9f000
0)
  object space 2330176K, 9% used [0x11660000,0x1e8514b0,0x9f9f0000)
 PSPermGen       total 68736K, used 64198K [0x09660000, 0x0d980000, 0x11660000)
  object space 68736K, 93% used [0x09660000,0x0d5118c0,0x0d980000)
}


If anyone has any suggestions for memory and garbage collection settings, I'd appreciate your thoughts.

tia,

jim

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