Is it safe to copy the database file?

Generally, it is safe to copy the database file. But, be cafeful:

If you copy it when Firebird server is shut down, there shouldn't be any problem, it's just like any other file on the system. Same applies for databases with no users connected.

Copying database file while it's in use is a bad idea. As Firebird might write new transactions during the copy process, your copy will most probably get corrupt. It's always better to do backup and subsequent restore.

If backup/restore is too slow for you, or you want to use some 3rd party backup tool that only supports file-copy, you can solve the problem with Firebird's nBackup tool:

- lock the database file with nbackup
- copy the file
- unlock it

Locking the database is this way does not prevent database from functioning. All transactions are written to a separate place, and once you unlock the database, they get merged into the main file.

For more information, read nBackup manual:

http://www.firebirdsql.org/manual/nbackup-lock-unlock.html