System Administration

[nancy rippey]

I have an application that is experiencing a problem and producing about 10 defunct processes a day. This is a production server and can not easily be rebooted. I am willing to live with this until the appl. folks can get it fixed since they do not seem to be causing any problems. I was always under the impression that zombie processes did no harm. My question is - are the zombie processes actually taking up any CPU, when I run top each process is using between 3-6% CPU.

Thanks in advance

[Volker Borowski]

Hi Nancy,

at least a zombie eat an entry from the process-table, so kernelresources need to be watched (maxprocesses).

Since you put this thread under databases, may be you can give us some more information to track down the real problem.
What database do you use, and what debugs (i.e. oracle-tracefiles) do you have ?

Volker

[Stefan Farrelly]

If top is showing the zombies using cpu then they are indeed using it. A zombie is a process which has received instructions to terminate but cannot do so due to an external reason - usually a tcp socket which is still open to that process which needs to be closed first.

If you use the lsof command this will show you which ip address is holding the zombie pids open, and then you can get the offending ip rebooted or the application closed down, and the zombie will die. Or you can used the ndd command on HP-UX 11 to terminate tcp connections manually, then the zombie will die all by itself.