[distcc] Remote Fallback

[Martin Pool]

On 21 May 2003, Thomas Walker <Thomas.Walker at morganstanley.com> wrote:

> You are correct about the reasoning... I am going to have a very
> large number of backend servers in the list that may, on occasion,
> not be available.  I was looking at just carefully managing the list
> so that I make sure that everything in it is good but that adds a
> reasonably significant amount of overhead.

Another thing you can do is have some kind of script that updates
/etc/distcc/hosts depending on the network state.  (Needing a separate
program to do it is perhaps ugly, but it allows some flexibility.)

> I've seen people on this list wondering whether distcc could be made
> to try other remote hosts before falling back but never saw a
> response.

> I was looking at the 2.3 code yesterday and it seemed to require a
> reasonably intrusive patch (make the hostlist static and reorder how
> some things are done in distcc.c to make the retry logic possible
> without repeating some things unnecessarily) but it sounds like you
> may have already made some of the changes I would need in 2.4.  I'll
> take a look at the new code and see what I can do...

I suspect remembering unreachable hosts may give decent performance in
this situation while still keeping things conceptually simple.  Let us
know.

In 3.x I'd like the client to simultaneously open connections to
several hosts and use whichever one is ready first.  That should also
help with this situation.  I don't think it would be worthwhile to
change it in 2.x, but of course you can try if you want.

-- 
Martin 

linux.conf.au 2004: Adelaide, Australia         http://lca2004.linux.org.au/