It currently is 700MB but it's conceivable that it'll grow beyond the 1GB. Normally I just copy this file to another location (for the curious, it's the database of a Zope instance, a ZODB file).
This file changes little from day to day, but I understand Bacula can't do inside-the-file subdivision for incremental backups. Anyway, it doesn't matter. What I want to do is a full backup daily and keep two of them and a full backup weekly and also keep two of them. So at any given time I can get yesterday, the day before yesterday, a week ago and two weeks ago. Would you think that's a good idea?
I suppose I should make two schedules, daily and weekly. But which numbers should I have on the volumes and the pools to achieve this? Two volumes of 1.5GB? Any hints or guidance is welcome, I'm not a sysadmin and my experience with Bacula is very limited.
Online backup of a large database file is risky business, as the file might change while you are reading it, rendering the backup inconsistent and possibly useless. I believe you should not be making backups of the ZODB file itself, but rather of diffs created daily by the repozo tool. This way, you also outsource the job of handling the inside-the-file subdivisions that you say Bacula is incapable of dealing with.