Re: Algorithms and Hashing (was: Re: Reread of config without restart)

From: Patrick Viet <patrick.viet#gmail.com>
Date: Thu, 13 Mar 2008 10:54:53 +0100


On Wed, Mar 12, 2008 at 8:10 PM, Michael Rennt <m.rennt#gmx.net> wrote:

> I see that the server identifier is stored inside the cookies. This is pretty
> good, as it keeps stickyness even when there's a failover to another equally
> configured loadbalancer.

> The only question left for now: How is all the hashing and distribution implemented?
>
> I see that the source IP (or whatever other parameter) is hashed and divided by
> the total weight of all servers. But what if a new server is added?
> Won't the stickiness be completely different after that, messing up any existing
> stickiness?

The hashing choice is done only if there isn't already a persistency cookie. Therefore the old sessions don't move, and the new sessions will benefit from the extra server.
You should really try the software. Nothing beats experience.

Patrick Received on 2008/03/13 10:54

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