I am looking for some advice on an optimal configuration for memcached, for a popular Movable Type (v4.23) blog that is moving from a single box config to a 2-box config, as described below.
Here is the "before" scenario of a busy live site: -Everything on one box (static html files, perl-based Movable Type (MT) app, mysql server) -box has 4GB RAM total -memcached running and enabled in MT 4.23, with 512MB allocated -based on memcached stats, the full 512 MB is not being used by memcached, even after doing a full rebuild, etc. Essentially memcached seems to be running well with the built support for memcached in MT 4.23. (Side note: I am a little surprised that the full 512 isn't being used, but I am not a memcached expert and I haven't attempted to calculate what the memory footprint of all the objects in MT should amount to. FWIW, there are thousands of blog entries and 50K+ comments, etc.) In any event, the "after" scenario looks like: Box 1 (same box as above): -static HTML files -MT app -box still has 4 GB RAM Box 2: -dedicated for mysql server (only the MT database) -box has *8* GB of RAM total -is on same local network as Box 1, connected via GB switch The question is: what to do with memcached? A few options come to mind, but I am not sure which is best: 1) Run memcached on both, leveraging memory from both servers (but does that make sense given that the current setup isn't using the 512 MB allocated?) If both, how much RAM to allocate to each? 2) Keep in the way it is, memcached running on the same box as MT, 512 MB allocated (rationale: don't seem to need more than 512MB, and local RAM is presumably fastest?) 3) Run memcached *only* on the DB box, and not at all on the MT app box (rationale: MT app/webserver box only has 4GB of RAM so best to save that RAM for apache/perl and take advantage of some of the 8 GB of RAM on the new DB box for memcached). Thoughts, advice? Thanks, Mark
