I've never had pbs disappear on me but I have had it turn into a zombie process on several occasions. At that point there's nothing I can do to fix it - kill doesn't work on zombies (even with -9) because it's waiting for the parent to acknowledge the death. I've tried starting a new pbs process but that didn't seem to solve anything. On all 3 occasions I ended up having to restart (logging out may have solved the problem, but I figure it doesn't take much longer to restart and you may as well do a full restart if you're going to log out anyway)
I've never had pbs disappear on me but I have had it turn into a zombie process on several occasions. At that point there's nothing I can do to fix it - kill doesn't work on zombies (even with -9) because it's waiting for the parent to acknowledge the death. I've tried starting a new pbs process but that didn't seem to solve anything. On all 3 occasions I ended up having to restart (logging out may have solved the problem, but I figure it doesn't take much longer to restart and you may as well do a full restart if you're going to log out anyway)