Miscellaneous questions

[Dag-Erling Smørgrav]

"Michael S. Fischer" <michael at dynamine.net> writes:
> Dag-Erling Smørgrav <des at linpro.no> writes:
> > I think the default timeout on backends connection may be a little
> > short, though.
> I assume this is the thread_pool_timeout parameter?

No, that's how long an idle worker thread is kept alive.  I don't think
the backend timeout is configurable, I think it's hardocded to five
seconds.

> I'm dealing with a situation where the working set of cacheable
> responses is larger than the RAM size of a particular Varnish
> instance.  (I don't want to go to disk because it will incur at least
> a 10ms penalty.)  I also want to maximize the hit ratio.

My knee-jerk reaction would be "add more RAM, or add more servers"

> One good way to do this is to put a pass-only Varnish instance (i.e.,
> a content switch) in front of a set of intermediate backends (Varnish
> caching proxies), each of which is assigned to cache a subset of the
> possible URI namespace.
>
> However, in order to do this, the content switch must make consistent
> decisions about which cache to direct the incoming requests to.  One
> good way of doing that is implementing a hash function H(U) -> V,
> where  U is the request URI, and V is the intermediate-level proxy.

That's actually a pretty good idea...  Could you open a ticket for it?

DES
-- 
Dag-Erling Smørgrav
Senior Software Developer
Linpro AS - www.linpro.no