I'm running a Tomcat 6 instance on a 34 GB EC2 instance. I've been struggling to keep the memory down but this thing services a lot of requests and the heap frequently gets up to 13 GB. But the heap is another story.
The real problem right now is that after awhile the server stops responding and console commands are met with a "fork: Resource temporarily unavailable" message.
Since the server goes down hard at this point and nothing is on the EC2 or ssh console I don't know how to diagnose this. After restarting and leaving up for awhile, top looks like this:
Mem: 35847580k total, 28719420k used, 7128160k free, 221432k buffers Swap: 0k total, 0k used, 0k free, 11103780k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND xxxx tomcat 25 0 19.9g 15g 9832 S 86 44.1 36:01.69 java
I'm pretty sure I have my ulimits set high enough and nothing in
/etc/security.conf that would limit the Java process. I've got about 30,000 threads and an equal number of FDs. Nothing either in syslog besides some SYN flodding messages (these happen when the JVM GC's and we're under heavy load)
Anything else I should look at? (