Memcached::addServers adds
servers to the server pool. Each entry in
servers is supposed to be an array containing hostname,
port, and, optionally, weight of the server. No connection is established
to the servers at this time.
The same server may appear multiple times in the server pool, because no
duplication checks are made. This is not advisable; instead, use the
weight option to increase the selection weighting of
this server.