[Brad]

Hi,

Quick answer; Yes vBulletin has support for them.


Long answer;

By default vBulletin does cache a lot of data (called the "datastore") however it's stored in the database (in RAM, not on the HDD). It's possible to also store it in the file system depending on your configuration.

The above options work on all servers hence them begin the default way of doing things. However vBulletin does support the use of APC and Memcached for managing the datastore. eAccelerator was supported in older versions of the software but it was disabled in later versions due to some issues caused by allowing eAccelerator to manage the datastore.

from class_datastore.php;

PHP Code:

    /*
    Unfortunately, due to a design issue with eAccelerator
    we must disable this module at this time.

    The reason for this is that eAccelerator does not distinguish
    between memory allocated for cached scripts and memory allocated
    as shared memory storage.

    Therefore, the possibility exists for the administrator to turn
    off the board, which would then instruct eAccelerator to update
    its cache of the datastore. However, if the memory allocated is
    insufficient to store the new version of the datastore due to
    being filled with cached scripts, this will not be performed
    successfully, resulting in the OLD version of the datastore
    remaining, with the net result that the board does NOT turn off
    until the web server is restarted (which refreshes the shared
    memory)

    This problem affects anything read from the datastore, including
    the forumcache, the options cache, the usergroup cache, smilies,
    bbcodes, post icons...

    As a result we have no alternative but to totally disable the
    eAccelerator datastore module at this time. If at some point in
    the future this design issue is resolved, we will re-enable it.

    We still recommend running eAccelerator with PHP due to the huge
    performance benefits, but at this time it is not viable to use
    it for datastore cacheing. - Kier
    */