On Sun, December 11, 2011 5:44 pm, Wietse Venema wrote: > Combining memcache and proxymap > ------------------------------- > > It seems that memcache is best for (surprise) doing what it was > designed for: a cache layer on top of a persistent database, where > the cache is maintained by the clients of the persistent database. > > This means doing something like this: > > /etc/postfix/main.cf: > postscreen_cache_map = memcache:/etc/postfix/postscreen-cache > > /etc/postfix/postscreen-cache: > # Where is the memcache server? > hosts = host1:port1 > > # Where is the persistent database? > persistence = proxymap:inet:host2:port2:persistent-database > > # Future: sharding (key hashing) to spread the load across > # multiple memory caches and persistent databases.
For memcache-level sharding (in the presence of dead/unreachable servers) you could just do something similar to Cache::Memcached->get_sock and Cache::Memcached::_hashfunc (see http://code.livejournal.org/trac/memcached/browser/trunk/api/perl/lib/Cache/Memcached.pm). Maybe for persistent sharding too, but they can use different functions for selecting servers.
