One of the last things to migrate to Dream Host is my collection of Gallery2 installations.
The biggest issue is a database disparity. On whip (my old server) my gallery2 installs were done using the multisite installation scheme on a PostgreSQL database. DreamHost supports only MySQL and gallery doesn't have an import/export function. So, I had two options: reimport the albums into fresh gallery2 installs or migrate the installations along with the data. I didn't want to loose all that meta-data so I gave migration a shot. These notes are being typed after doing the process a 2nd time. Learn from my mistakes!