Home directories on NFS

Alvin info at alvin.be
Tue Mar 24 19:52:53 UTC 2009


On Tuesday 24 March 2009 17:49:08 Michael Hirsch wrote:
> On Mon, Mar 23, 2009 at 8:46 AM, Alvin <info at alvin.be> wrote:
> > I'm having major difficulties with a new server setup. Maybe it's a bit
> > much to want at once, but here is what I want:
> >
> > - Ubuntu server with kvm/qemu [DONE]
> > - Ubuntu JeOS with Kubuntu on that server [INSTALLED]
> > - remote acces with XDMCP [DONE]
> > - Home directories on NFS share [?]
> >
> > Well, installing everything was no problem, but I have several
> > difficulties. I tried using a Solaris 10 server with ZFS filesystems as
> > NFS server. Performance was horrible. Starting any program (like Dolphin)
> > took several minutes. Moving a window was something that could be done
> > with a lot of patience.
> >
> > Thinking it was the Solaris implementation of NFS, I tried using the
> > virtual host as an NFS server. That worked a whole lot better. Desktop
> > performance is very good.
>
> In general, if only home dirs are on NFS I wouldn't expect much
> performance impost on application startup.  I suppose if the
> application is also stored in the home dir there would be performance
> impact.
> 
> In general, whene I have unexplained performance problems, look at
> your networking.  If DNS is not working right, that could explain the
> pause.  A firewall could prevent identd or some other server from
> working and the pause could be caused by waiting for a timeout.

Networking is no problem. I don't understand the Solaris NFS troubles. That 
server is serving a lot of other machines without any performance issues, but 
putting your home with KDE on it just doesn't work.

In the second case, we're talking about NFS from a virtual host to his virtual 
guest. There's no physical wire, so I'm not worried about speed. No firewall, 
no DNS.

> > However, now I noticed that Akonadi does not work. It just will not
> > start. The first time, akonadi took the whole virtual machine down during
> > the time where you see the program bar. (That's right. I couldn't even
> > get in with ssh anymore.) I already tried setting the apparmor profile to
> > complain instead of enforce. This makes no difference.
> >
> > What could I be doing wrong? I'm starting to fear Akonadi just doesn't
> > like NFS, but that would be a disaster. Can anyone confirm this?
>
> You could use strace to see what akonadi is doing when it starts.  Is
> everything slow, or are there particular calls that make it hang?

It's not slow. It crashes X the first time, and other times, it just won't 
start.

Today, I used a virtual qemu2 disk and mounted that as /home.
Everything works as it should. Akonadi still takes the X server down on its 
first start when you use XDMCP, but after that first session, it behaves.

Conclusion: Akonadi DOES NOT work on NFS shared homes. Therefore, KDE no 
longer works on NFS, and that is truly a shame.




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