Adding block-level replication

DRBD is the next component of our software stack. Unlike LVM, it requires at least two servers to function normally. One server acts as the Primary data server, and the other acts as a Secondary. These roles can be switched at any time, depending on which server is running PostgreSQL.

This recipe will focus on configuring and activating DRBD as part of our stack.

Getting ready

By now, we hope you've followed the steps in the Getting started with the LVM recipe for two servers with /dev/sdb as the physically identical pieces of storage on each server. While DRBD can operate in standalone mode on a single server, this is actually a more advanced usage. The steps in this recipe are best applied...