Re: kill: cannot kill some processes

[brian moore <bem@cmc.net>]

On Sat, Mar 03, 2001 at 08:52:36AM -0500, Cory Snavely wrote:
> Right now on a big Solaris machine of mine I have about a dozen zombied
> Perls--parent process (Apache) long gone, and when I -9ed them, their PPIDs
> became 1 (init). Classic zombie.

Hrrrm?  Not quite.  Init eventually inherits zombie children (when the
parent dies), but init reaps the dead children.  Perhaps your children
aren't dead?

> Problem is, these Perls are running scripts off a software RAID, and thus
> have it locked. This happened before--when I reboot the server to get rid of
> the zombies, or some other reason, the filesystem won't unmount, won't get a
> clean flag, and therefore will force fsck on reboot. As it's over 100GB, a
> full fsck takes several hours.
> 
> Now maybe there's something I don't know to recover from this cleanly, or
> maybe Linux handles it a different way, but it seems like this is an example
> of zombies causing a real problem. If anyone knows a way around it, I'd be
> real grateful!

Doesn't sound like a zombie to me.  A zombie has -no- open files and goes
away as soon as init inherits it.  A zombie is in state 'Z' on ps.

What you describe sounds more like something in state 'D', which is
waiting for IO to complete.  (This can happen on NFS when things break in
just the wrong way for some reason.)  They're not zombies because they're
not dead yet (they need to release their files before they are really
dead).

For processes stuck in a 'D' state, there is very little you can do about
them.  You may be able to sneak out of re-fscking by remounting the drive
read-only before rebooting, though.

-- 
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