[squid-users] Multiple-Instance Questions

I've been inspired by the recent discussions to set up my own multiple-instanace Squid box. I've got it running with some real connections in a basic config, and I think I've got most of the general config issues worked out.

I have questions about some of the advanced tweaking and how it works with multiple instances, and I'm also looking for a general sanity check on my config...

We have 7 instances of Squid 2.7STABLE running on a single box right now. 2 are "frontend" (used by clients), and 5 are "backend" (parent peers to the frontends).

The frontend instances have all the ACLs, delay pools, and access logging. They are configured for memory-only caching (no storedir), and max out at 4GB process space.

The backend instances have small cache_mem and have the storedirs defined. They don't do any delay pools, ACLs or logging (unless I need debugging).

I'm wondering:

 - Do delay pools work properly if they're only on the frontend, or are they ignored if a peer handles the request for us? I'm hoping they do, otherwise there's no good way to enforce consistent limits when spread across 5 backends.

 - If I use a rewrite program, should I have it on just the frontends, just the backends, or all instances (I'm not sure how the rewrite affects peer requests)?

 - Similarly, should I use storeurl_rewrite_program on the frontends, the backends, or all instances (I suspect it should be "all")?

 - I'm using round-robin for the backend peer selection. Should I switch to carp, or is that overkill when the instances are on the same physical box? What advantages does carp have?

Thanks,

Jason

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Jason Healy    |    jhealy@logn.net    |   http://www.logn.net/