topic Re: kill ghost processes in Operating System - HP-UX

kill ghost processes

DIEGO_40 — Tue, 08 Feb 2005 17:30:09 GMT

Hi all,
how I can kill ghost processes?I know kill -9 but it fail...Is there a specific command for kill this processes?? I have trouble with oracle process

Thanks!!
Ciao

Re: kill ghost processes

A. Clay Stephenson — Tue, 08 Feb 2005 17:36:33 GMT

I assume that by "ghost" processes you actually mean "zombie" processes. You can't kill them (because they are already dead and can certainly never respond to a signal which is all a kill is). Zombie's consume no resources (other than a process table slot) and do no real harm. You may be talking about a process that is waiting on an io event; these too cannot respond to a signal because they are waiting on a higher priority event --- like an io request to complete.

Re: kill ghost processes

David Child_1 — Tue, 08 Feb 2005 17:40:00 GMT

Diego,

If you are refering to processes then you may be out of luck. To clean these up you would need to kill the parent proceses so if the parent process ID (PPID) is 1 a reboot is your only recourse.

Perhaps you could provide an an output of 'ps -ef'.

Also, 'kill -9' should be discouraged. Using it is often what causes these processes since it doesn't clean up.

David

Re: kill ghost processes

Robert Salter — Tue, 08 Feb 2005 17:41:51 GMT

Ghost processes, do you mean the ones that have a parent of 1 or defuncts. Either way, if kill -9 doesn't do it a reboot will and sometimes that's the only way.

The Great Almighty Wizard of 1z, does a lot of cool stuff, then goes burp and becomes a nudnick. Nothing to do at that point but put 'em out to pasture.

If the ghost processes aren't taking up any resources, let them hang out until you can schedule a reboot.

L8tr

Re: kill ghost processes

DIEGO_40 — Tue, 08 Feb 2005 17:53:07 GMT

When I kill them with the option -9 they still running (ps -ef|grep ),only the day after I don't have more the problem, but in meantime I can't shutdown the oracle istance...I don't want reboot the machine (this is the last chance) because a lot of people is connected to this machine(partition of superdome). My friend who worked with me knew a method for kill this processes, is possible??

Thanks a lot!
Ciao

Re: kill ghost processes

David Child_1 — Tue, 08 Feb 2005 18:01:47 GMT

It sounds like they are waiting on I/O and therefore don't die right away. Unfortunately there is no way to kill a process waiting on I/O. From what you said it appears the processes finally die so I would recommend against using the '-9'. Just kill it and wait for I/O to finish.

You may want to take a look at your I/O subsystem to see how its running. Does 'sar 5 5' show high WIO%?

David

Re: kill ghost processes

A. Clay Stephenson — Tue, 08 Feb 2005 18:04:41 GMT

If these are zombies processes then nothing other than a reboot will remove them but again, they do no harm. You might try a shutdown abort on your database but that is about as drastic as a kill -9. Kill -9 is one of those things that should be used as a weapon of last resort because it is the very thing that can cause the kinds of problems that you are seeing. When a process receives a SIGKILL (kill -9) absolutely no cleanup (detaching shared memory, removing temporary files, etc.) can be done.