Why I Married pg_migrator

With the introduction of PostgreSQL 8.4, Bruce Momjian, a significant core developer, contributed a tool that can actually upgrade an entire database cluster in place. The time required is essentially only that necessary to copy the data files from the old installation to the new one. On a quick RAID system, this can be an order of magnitude faster than a dump/restore. The main drawback is similar to Slony: disk space must effectively be doubled for this upgrade method.