Postgresql is generally faster than mysql. Fitting it onto an embedded system is either memory or storage constraints, but postgresql is equal or better in bot

Postgresql is generally faster than mysql. Fitting it onto an embedded system is either memory or storage constraints, but postgresql is equal or better in both those regards so I can't imagine what problem you had. Replication is dead simple with postgresql as well, with the added bonus that it doesn't randomly die and require manually intervention to get it working again.