UNIX for Dummies Questions & Answers

Hello


I try to googled it , but I dint get sufficient answer ..
When I can see zombie running on server do they consume system resources or not ?
I have read that is not good to kill them with signal 9 cause it might cause more troubles .. why is kill -9 so harmfull?
thanks

You cannot "kill" a zombie process. They are usually cleared up automatically by unix unless they are stuck talking to some I/O device in which case only a reboot will get rid of them.

I have assumed that you know the difference between a Zombie Process and an Orphan Process. Here is a detailed explanation of a Zombie Process:

Zombie process - Wikipedia, the free encyclopedia

As for "kill -9" it is rarely ever necessary to issue "kill -9" unless you are having trouble shutting down a sick computer. A "kill -9" ends the process uncleanly and is one of the easiest ways to silently corrupt files.

methyl is right on about kill -9.

zombies use no resources except one - they use a process entry slot. Unless you have really large numbers of zombies that is usually not a problem.

zombies are caused by the parent process doing something stupid, namely not wait - ing on a child process. This can often be caused by blocking SIGCHLD with SIG_IGN. In that case the only way for the zombie to go away is when the parent exits, and init adopts the zombies. One of init primary jobs is to wait for parentless processes, adopt the zombie process and then wait for the zombie so it can leave and go to heaven.

I personally think people's aversion to zombies has more to do with the movies and popular culture and very little to do with what they do to unix boxes. It's all in the name.