Postgres vs Firebird [closed]

Answer 1

File System based backups possible
Yes(Postmaster must be stopped)

is not true. since 8.1 (if i remember correctly) it's possible to activate WAL archiving and then creating filesystem based backups without shutting down anything. Look for PITR (point-in-time-recovery) in the docs for more information

Answer 2

For those who are using Firebird, I would suggest reading the Firebird 2.1 Release Notes to understand a database corruption issue wrt to older Firebird versions running on Linux.

In short it has to do with a bug in Linux. For older Firebirds, the workaround is to mount the affected filesystem with the sync option. The problem is fixed in FB2.1.