Bob Crandell wrote:
> Hi,
> I have a server with a growing number of these:
> 20344 ? Z 0:00 [sh <defunct>]
> 20354 ? Z 0:00 [sh <defunct>]
> 20355 ? Z 0:00 [sh <defunct>]
> 20363 ? Z 0:00 [sh <defunct>]
>
> How do I get rid if them? How do I find out what's causing them?
Use "ps fax" to see who their parent process is. (You can also look
at the PPID field with "ps lax", but "ps fax" is easier to read.)
The only way to get rid of them is to fix or kill the parent.
What's happening is that those processes are zombies. They've exited,
but their parent(s) haven't waited on them. So the process hangs
around in zombie state, with just enough information for the parent to
extract their status (exit status, which signal killed them, whether
there was a core dump, and what resources they consumed).
If a parent exits before the child, the child becomes an orphan and is
given process 1 (/sbin/init) as its parent. Init always waits on its
children.
If you're writing the parent, and you don't want to bother waiting for
the child, you can disinherit it by making it your grandchild. In sh,
you'd replace this:
long_running_process &
with this:
(long_running_process &)
The parentheses create a subprocess, which only exists long
enough to create the subsubprocess (grandchild).
--
Bob Miller K<bob>
kbobsoft software consulting
http://kbobsoft.com [EMAIL PROTECTED]
