Client interoperability, server selection.

[Josh Snyder]

> Problems with Ketama implementation in libketama as of 0.1.1 are (I
> know there's a newer release, so maybe some are solved already?):

One more to add -- the consistent hashing is not quite perfect, in
that adding/removing a server causes some unrelated items to get
rehashed to different servers. There's a (too) long email about this,
including tests and an explanation of why it happens, at:

http://lists.danga.com/pipermail/memcached/2007-October/005588.html

See also Richard Jones' recent comments at

http://lists.danga.com/pipermail/memcached/2008-March/006551.html

It is not a critical problem (in an out-of-the-box test, only between
5% and 10% of items get rehashed unnecessarily), but if we're shooting
for a standard, it might be worth trying to resolve.

-josh