On Mon, Sep 01, 2008 at 02:20:47AM -0700, elsergio wrote: > Which option is better for using Squid as a Load Balancer? > > a) Multi thread processor. > b) Non Multi thread processor. Non multi-thread/core processor is only to be preferred if you can get a faster processor at the same price, i.e. if you can trade processor pipelines for raw speed. Even then, you'd probably only want to do that if you're gaining quite a bit of speed. Squid itself is a single-process, single-threaded application, so cannot take advantage of more than one processor pipeline. Theoretically then, a faster CPU that can only run one thread/process at a time is better than a slower one which can run 2 or more threads at the same time simply because squid itself can only make use of a single pipeline. However: many (most?) squid configurations make use of external processes, such as URL rewriters and authentication helpers. Since they're separate programs they can take advantage of parallel execution provided by the CPU. You can also use diskd or aufs to move the disk access to another process (though that's more I/O intensive than CPU intensive). In addition, even a dedicated server will have some background processes happening (time sync, admin logins, logging, etc.). Therefore, you're almost guaranteed to have other processes that would like to run at the same time as squid regardless of your squid configuration. Therefore, my best guess is that dual-core CPUs are the way to go. Additional cores will probably only be helpful if you have lots of additional helper processes running simultaneously, or if the server is doing things besides running squid. Another thing to consider is running multiple squid instances on the same server. In that case, more cores (or physical CPUs) will definitely help, but whether or not it's feasible depends on what you want to do and how you want to do it. Okay, after having written all that I managed to find the recent thread which discussed this in some detail, so you might find this to be worth a read: http://www.archivum.info/squid-users@xxxxxxxxxxxxxxx/2008-07/threads.html#00454
