[ale] Lab Workstation Mystery

[Jim Kinney]

Anyone using screen, tmux or nohup? 
On Wed, 2016-04-20 at 11:52 -0500, Todor Fassl wrote:
> I posted about this problem a couple of weeks ago and still have not 
> figured it out. The problem is that on a group of machines running 
> ubuntu 15.10, after a period of time, mounting home directories via
> NFS 
> hangs. Attempting to mount or unmount home directories via NFS
> simply 
> hangs. Eventually, the root filesystem getsremounted read-only and
> the 
> machine becomes unusable even as a local user. One thing I've
> discovered 
> since my first post about this is that when end-users log out, some 
> processes do not get killed off. The automounter can't umount the
> home 
> directory because the user still has some processes running.
> Eventually, 
> the machine has several home directories mounted via NFS for users
> who 
> are no longer logged in. I am thinking that what is happening is
> that 
> eventually this causes NFS to get wedged which in turn leads to the 
> kernel freaking out. Or something. Here is an example of the output
> from 
> listing the processes for a user who has logged out:
> 
> # ps -u enduser1
>      PID TTY          TIME CMD
>   101794 ?        00:00:00 systemd
>   101795 ?        00:00:00 (sd-pam)
>   103049 ?        00:00:00 ibus-daemon
>   103057 ?        00:00:00 ibus-dconf
> 
> 
> So frequently, even though a user has logged out days ago, the
> systemd 
> and ibus-deamon might still be running. I am thinking after enough
> time, 
> these things mess up the nfsv4 kernel module which eventually messes
> up 
> the kernel itself.
> 
> But why would logging out *not* killoff all of an end-user's
> processes?
> 
> 
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-- 
James P. Kinney III

Every time you stop a school, you will have to build a jail. What you
gain at one end you lose at the other. It's like feeding a dog on his
own tail. It won't fatten the dog.
- Speech 11/23/1900 Mark Twain

http://heretothereideas.blogspot.com/

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