Linux Resource Troubleshooting Commands

Command that reveal the inner workings of our machine

ulimit
free
vmstat
netstat
sysstat
mpstat
iostat
ping -c 1
traceroute 
sar

What is the process consuming the most CPU
ps -eo pcpu,pid,user,args | sort -k 1 -r | head -2


What is the memory usage after 16:30 ...
   sar -s 16:30:00 -r
What is the disk paging after 16:30 ..
   sar -s 16:30:00 -B
Another day on I/O and mem usage
sar -f /var/log/sa/sa12 -u -n SOCK -B -r -s 15:30:00 -e 16:10:00

If you used previous versions of jvmstat you may be familiar with some of the older names... Here is a mapping of the old names to the new names:
JDK 5.0
jvmps is now jps, sse docs
jvmstat is now jstat
perfagent is now jstatd
jvmstat 3.0
visualgc is still visualgc