[CentOS] Diagnosing random hangs

On 12/18/06, Mark Belanger <mark_belanger at ltx.com> wrote:
> Matthew Miller wrote:
> > On Mon, Dec 18, 2006 at 04:17:59PM -0500, Mark Belanger wrote:
> >> I have many different centos machines that are hanging
> >> regulary.  I believe this is due to something our application
> >> is doing - not a centos specific problem.
> >> When the machines hang, there is no access to the console
> >> or remote access(ssh, rsh, etc).
> >
> > Do you mean that there's no *access* to the console, or that it doesn't
> > *respond* on the console?
>
> X is frozen, no way to switch the console(i.e. Ctrl-Alt-F1, Ctrl-Alt-Backspace),
> and no way to access the machine remotely.
>
Consider setting up a serial console so that you might be able use
magic-sysreq to gather infomation on the kernel and processes.  The
serial console should not be effect by X freezing (i.e. you would have
a seperatate terminal session setup too it, prefereably in a GUI
environment not on that machine.

Cheers...james

P.S. The documentation on magic sysreq is in the kernel docs.