show stopper for us: dev nbd0 clients locking up losing connection with server

Scott Balneaves sbalneav at
Tue Sep 16 00:23:35 BST 2008

On Mon, Sep 15, 2008 at 03:04:19PM -0700, john wrote:
> Hi Scott,
> >
> > Well, if you're not doing a huge amount of stuff with graphics in firefox or
> > Gimp, you probably won't need the swap, so I'd turn it off if it's making
> > things worse.
> Ok, thanks. Is there a place I can go to get a feel for how ltsp
> currently works? Is there a doc/web page etc that
> sort of says here's how we implement LTSP since 7.10 and here's some
> options you can work with e.g
> you can edit  "/etc/ltsp/nbdswap.conf" etc?

The Edubuntu Handbooks got a lot of stuff.  It's *slightly* out of date, we're
working on moving the docs into the LTSP project itself, and updating them, but
just about all the info in it's good.

> Sadly most of them are dumb as well. I believe one may be able to do
> logging remotely. I'll look into turning that on.
> One intersting note:
> When I showed a *nix guru I know the log messages :
> Sep 12 10:34:44 kernel: [679871.912346] end_request: I/O
> error, dev nbd0, sector 200140
>  Sep 12 10:34:44 kernel: [679871.912363] end_request: I/O
>  error, dev nbd0, sector 200142
> He pointed out "those sector numbers are just a hair above 50 megs.  Have you
> looked at the block files which are being served for the clients (I believe
> they're in /tmp)?  I wonder if the files aren't being sized correctly for
> the swap space they need to serve."
> Dunno if this rings a bell with you, but I"ll be look into that next.

Hmmm. Well, we use mksquashfs, which figures out the size of the image itself,
we never touch it, so unless it's guessing wrong.

I know this is going to sound like a completely stupid question, but have you
rebuilt the image with ltsp-update-image?  Chroot into the /opt/ltsp/i386,
upgrade the image, rebuild it, and re-run ltsp-update-kernel.

Just for a laugh.


Scott L. Balneaves | "There are many causes I am prepared to die for,
Systems Department |  but no causes I am prepared to kill for."
Legal Aid Manitoba |    -- Mohandas Karamchand Gandhi

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