Rackspace Cloud Site Hosting Random 500 Errors

[Bryon] Ok yeah, this is an XCache problem, they have a bug in their deployed version which can rnadomly cause this type of issue (http://xcache.lighttpd.net/ticket/291), we've been working with them to try to isolate the issue but I don't believe it's been fully solved yet. XCache can be disabled through htaccess commands to mitigate the issue in the interim

[Bryon] To disable xcache, add the following to the .htaccess file:

php_flag xcache.size 0
php_flag xcache.cacher off
php_flag xcache.stat off