Hello, Chee!

Monday, June 24, 2013, 4:39:31 PM, you wrote:

CY> Each release of Firebird has it own gbak.exe.
CY> I am just wondering if I can use any version of gbak to
CY> backup/restore any version of firebird database?

gbak is not a spherical horse, it related to the
ODS (database structure), because it need to know all new
metadata changes that is new for the new Firebird version.

Thus, gbak have it's own backup format, to be understood
by the previous versions of gbak (is it compatible or not).
Usual compatibility is from top to bottom,
i.e. gbak from FB 2.5 can understand previous backup formats.

CY> For example, can I use gbak.exe from Firebird 1.5 to
CY> backup/restore Firebird 1.5/2.0/2.5 database?

gbak makes backup only in it's native format.
If you will use gbak from 2.5 with Firebird 1.5, you can make
backup, but can't (probably) make restore (from 2.5 format), because
Firebird 1.5 itself does not know anything about 2.5 features.

Also new versions of gbak sometimes have new features.

CY>Or can I use gbak.exe from Firebird 2.5 to backup/restore Firebird 1.5/2.0/2.5 database?
you may use gbak from 2.5 to backup db's from 2.5 and to restore
backups from 1.5 and 2.x.

CY> I have tried it and it seems work. Is it advisable to do so?

In common, this is pointless, and can be used only in rare
cases (including repairing old databases) to migrate "down",
for example, from Firebird 2.5 to Firebird 1.5 (here you need gbak
from 1.5).
No guarantee of success for this kind of migration, of course.

So, finally, you should use same gbak version that Firebird server have.

btw, what idea you have with that "compatibility"?

--
Dmitry Kuzmenko, www.ib-aid.com