Subject Re: [firebird-support] Incremental Backup
Author Konstantin Khomoutov
On Thu, 27 Jun 2013 15:21:51 -0400
"Leyne, Sean" <Sean@...> wrote:

> > You are right. Now a days gbak indeed takes arounda five 5 minutes.
> >
> > I was thinking about use nbackup for additional "log".
> > I would make incremental backup every 5 minutes (for example) and
> > so I could restore the db situation in any 5 minutes I need.
> >
> > Is it a good idea?
> You would need to also have hourly/daily incremental backups.
> Since in order to recover using an incremental you would need to
> restore the last full backup, as well as each the last daily, last
> hourly and each 5 min incremental, to perform a "point-in-time"
> recovery...

Actually not. A backup session of level N > 0 copies all the data
since the backup of level N - 1 ended, so should the OP take only, say,
level 1 backup each 5 minutes, each backup file will contain the data
which could be used to combine the last 0-level (that is, full) backup
with the last incremental one. Combining the last full backup with some
other (earlier) incremental would provide for PITR. I'd say it's a
viable approach unless the database receives really heavy changes so
that doing only level 1 incrementals would copy too much data each time.

Also the OP should be aware of the fact if they intend to implement
incremental backups, full backups should also be done with nbackup --
IIUC it's impossible to apply files created by nbackup containing
backups of levels > 0 without also having lower-level backups created
by nbackup. And AFAIK these files are not portable across different
systems (machine word- and endianness-wise), and this should also be
considered before implementing such a scheme.