Prior to version 3.0.3 of the PHP memcache extension, compression is not enabled by default. This is okay when storing large objects from version 3.0.0 onwards as one gets a PHP notice
SERVER_ERROR object too large for cache. Before this version however, it's trickier to figure out what's going on. Boolean
false is returned from the save when it does fail before 3.0.0 which is something.
To disable compression in memcache in versions 3.0.0 of the extension and above, set
memcache.compress_threshold to 0.