With WAL-E installed, we can now use it to transmit transaction logs to and from our cloud service of choice. Remember, by keeping WAL files in a remote location, they're isolated from natural disasters, datacenter outages, being overwritten, and any number of unplanned events. Consider cloud storage a form of long-term archival of our transaction logs.
Why is this important? Remember our mantra: outages are unavoidable. We can take multiple steps to avoid them, but sometimes the situation is beyond human intervention. Sometimes we simply need to rebuild.
An offsite backup of WAL files means we can apply PITR to a recent backup and reach the last known stable state of our data. Since WAL-E integrates directly into the PostgreSQL transaction log archival process, the WAL files we preserve are as fresh as possible.
Let's see how it works.