High Availability Memcached

[Buooy]

So I have a high availability setup with a load balancer to two wordpress servers with wordpress-pecl-memcached-object-cache installed.

Obviously when one cache is updated, the other is not. If I specify each individual server IP in global $memcached_servers, does it mean that when one memcached is updated, the other will be concurrently updated?

[jpptinsley]

IIRC, it depends on your memcached settings -- it's the memcached client library duplicates objects across servers.

You specifically want to check the /etc/php5/conf.d/20-memcached.ini (or related) settings. There's guides available via googling, I don't have the settings to hand right now.

Really, though, the default is that memcached client will halve the hash space across the two memcached servers, so each gets half the objects. Should one fail, the other will take the full load.