Any insight on the sendstats balance method ?

Mark Smith marksmith at
Fri Oct 29 10:01:45 PDT 2004

This is implemented in LiveJournal via a module we link in with our

That module is responsible for sending out information about this Apache's
current status.  Perlbal can then use that information to balance.

We used to use this, but we don't use it for balancing anymore.  We
found that the most effective and efficient way of load balancing is by
using verify_backend, persist_backend, and a balance_method of random.

This will have at most N+1 connections open to any backend, where N is
the number of available connections it can serve.  Perlbal won't send
traffic to it unless it knows it's active.

This (random balancing + the options mentioned) is what we use on
LiveJournal, and it works well for us.  Let me know if you have any

On Fri, Oct 29, 2004, Yusuf Goolamabbas wrote:
> Brad, The round-robin (doesn't seem to be implemented at present) and
> random balance method for web_proxy SERVICE are self explanatory.
> Could you elaborate a bit on the sendstats balance method ? 
> According to the docs, the StatsListener classes listens for UDP
> broadcasts from web nodes describing how many children they have. Is
> this via some other Apache module ? How would this work for a non-Apache
> web-node
> Regards, Yusuf
> -- 
> Yusuf Goolamabbas
> yusufg at

Mark Smith
junior at

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