Mirroring Moodle
From MoodleDocs
Disc Mirroring
A technique in which data is written to two duplicate disks simultaneously. This way if one of the disk drives fails, the system can instantly switch to the other disk without any loss of data or service. Disk mirroring is used commonly in on-line database systems where it's critical that the data be accessible at all times.
Moodle can be utilized across several computers, mirrored to provide support and redundancy. A lot of people would benefit if someone could tell them how this can be done.