Presuming that we have all of the hardware and software we discussed earlier, our servers are still missing the following three things:
- The ability to synchronize data to two servers simultaneously
- The capacity to freeze data to prevent changes for backup purposes
- A durable filesystem designed for multiprocessing I/O
There are several solutions for each of these missing elements, yet we've settled on three in particular: DRBD, LVM, and XFS. Let's explore a bit about each of these technologies and discuss why we've chosen them for mirroring data at the server level.
