> Hello,
>
> I have got few quite basic questions about usage of gbak backup utility.
>
> gbak is version LI-V1.5.1.4500 Firebird 1.5
>
> 1)
> Is it safe (regarding to database being backed up) to interrupt
> gbak by signalling? Is SIGINT fine?
> If I do this, fbserver thread that worked for gbak seems to continue
> in its work. Is there a way to stop this thread safely at runtime?
> If no, is it safe to restart the database server in such a state?
> In case of safe restart, will I get rid of this post-mortem
> activity permanently?

gbak runs in it's own transaction context, whatever you do to the server of
the thread running gbak will have the same effect as stopping any other
transaction.
in the case of gbak, it's a read only transaction over the database so
stopping it or the server mid stream will have very litle risk of corrupting
the db.

>
> 2)
> Has database filename extension ".gdb" any specific influence on gbak?
> Could gbak behave differently if the extension was ".fdb" or
> whatever else?
>

no you can name a firebird database as you like - any extension is fine

> 3)
> Is it safe to run 2 instances of gbak on the same database?
> Perhaps when I find out that backup with garbage collecting
> will take hours, can I safely run another "gbak -g ..." ?
>
> TIA, Ferda
>

again - it runs in it's own transaction context so you can run as many gbaks
simultaneously as you like or as the server resources permit.
just remember - quorted from Helen recently:

"Yup. Do the backup *without* the -g switch, so that you clean out your
garbage. I know this switch is confusing, but -g means "no garbage
collection". All that deleting will have accumulated a mountain. Allow
plenty of time - it will take hours."

Alan