On Tue, Mar 8, 2011 at 12:24 PM, Michael Eager <eager at eagerm.com> wrote: > Hi -- > > I'm running a server which is usually stable, but every > once in a while it hangs. The server is used as a file > store using NFS and to run VMware machines. > > I don't see anything in /var/log/messages or elsewhere > to indicate any problem or offer any clue why the system > was hung. > > Any suggestions where I might look for a clue? Please be more specific when you say it "hangs". Does it just pause for a minute and then continue working, or does it freeze completely until you reboot it? Does it respond to s "soft" reboot like Ctrl-Alt-Del, or do you need to hard power it off? Since this is an NFS server I'm going to guess there might be a lot of IO. Maybe there is some large IO load going on, like maybe all your VMs are running anti-virus scan at the same time, or something like that. To troubleshoot, I recommend installing the 'sar' utilities (yum install sysstat) and then reviewing the collected data using the 'ksar' utility (http://sourceforge.net/projects/ksar/). sar/ksar are good for tracking down acute problems.