memcached persistent load balancing with an f5 big-ip

Brad Fitzpatrick brad at
Tue Jun 6 20:43:43 UTC 2006


On Tue, 6 Jun 2006, Matthew Kent wrote:

> Thought I'd share something handy I cooked up based on examples:
> If you have a f5 big-ip load balancer in your network (running some of
> the more recent software) you can use an iRule to distribute data to a
> pool of memcached servers based on a crc32 of the incoming key. The
> payload will be reexamined for each get/set request, allowing you to
> leave the connection open indefinitely.
> Although most (all?) of the client apis seem to handle multiple
> memcached servers and them being up/down, this seemed like a more
> graceful approach to provide 1 unified ip for my configs plus solve some
> issues with different apis (apr-util, ruby, php) hashing data between a
> 3 server group differently, making it annoying to share.
> Not in production yet but seems fine in testing.
> Oh and it does assume your memcached servers have an equal amount of
> ram. I haven't looked into how to implement weighting as I don't need it
> presently.
> --
> Matthew Kent <mkent at>

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