Thank you for the list of fantastic advice, that is very helpful.
The servers we have been buying have 128 gigs of RAM and all run SSD drives.
We will be using NGinx due to it being event based rather than thread based.
We will use APC PHP op-cache
Is https://tracker.moodle.org/browse/MDL-31501 still a valid deployable solution for a 2.4 or 2.5 instance of moodle? Or are we going to have to figure out our own memcached sessions?
For the shared file storage will GFS suffice?
Am I able to use Moodle 2.4s new session cache features
Again, thank you for the very helpful guide lines.