Running nexus on Amazon Linux on my SC2 instance. Clean install, then I built a small project against it. Not being used by anyone but me.
When I first start Nexus, CPU utilization starts out at 97% and memory usage at 20%. After a few minutes, it'll settle out to like 2-6% CPU and anywhere from 20-40% memory. On a 640MB instance, that means anywhere between 128 and 256MB! Doesn't seem right, especially since Nexus advertises itself as only needing 28MB. What's the deal?
Here's the readout from ps aux, if that helps :
root 25227 0.0 0.1 16980 692 ? Sl 16:05 0:00 /mnt/vol1/nexus-oss-webapp-22.214.171.124/bin/jsw/linux-x86-64/./wrapper /mnt/vol1/nexus-oss-webapp-126.96.36.199/bin/jsw/linux-x86-64/../conf/wrapper.conf wrapper.syslog.ident=nexus wrapper.pidfile=/mnt/vol1/nexus-oss-webapp-188.8.131.52/bin/jsw/linux-x86-64/./nexus.pid wrapper.daemonize=TRUE wrapper.lockfile=/var/lock/subsys/nexus root 25229 3.0 20.0 1247852 122628 ? Sl 16:05 0:12 java -Dsun.net.inetaddr.ttl=3600 -Dbasedir=. -Djava.io.tmpdir=./runtime/tmp -Djava.library.path=bin/jsw/linux-x86-64/lib -classpath bin/jsw/li b/wrapper-3.2.3.jar:./runtime/apps/nexus/lib/plexus-classworlds-2.4.jar:./conf/ -Dwrapper.key=GZhnIo3i5ox4LVLp -Dwrapper.port=32000 -Dwrapper.jvm.port.min=31000 -Dwrapper.jvm.port.max=31999 -Dwrapper.pid=252 27 -Dwrapper.version=3.2.3 -Dwrapper.native_library=wrapper -Dwrapper.service=TRUE -Dwrapper.cpu.timeout=10 -Dwrapper.jvmid=1 org.codehaus.plexus.classworlds.launcher.Launcher
(and yes, I know I shouldn't be running as root. this is only a test)
I should also add that at one point, I asked nexus to index the maven central repository, and when I did this, CPU utilization went skyhigh, between 30% and 90%, and stayed that way until I finally killed the process.