Creating this at Matteo's suggest in https://moodle.org/mod/forum/discuss.php?d=222250.

This is my scenario. We currently have Moodle 2.4 in dev and test environments and will be setting up a production environment over the next couple of months. (We have been running 2.2 for the past couple of years.) We just realized that with the new caching framework (MUC), we should not have $CFG->cachedir on a NFS mount. Instead, we would like to put it on local disk on each of the eight production servers we are running.

Putting cachedir on local disk on each server seems straightforward except for one thing: Cache purging does not work in this scenario. That is the bug I am reporting.

If it is not a bug, but simply the case that local disk cache is not compatible with a cluster, any recommendations for this scenario? Memcache?