This was originally posted on my family blog on 4/7/06. I will be slowly moving the geeky stuff from there to this blog.
I broke out the mondo man page. To verify my little backup, and see what has changed since I made it, I ran this:
mondoarchive -V -i -I "/home/bryan/Documents" -d '/mnt/home/backup3' -g -s '700m'
I had made a little change in a text file, and it flagged it and told me. I just noticed that it says the -I switch is ignored if you are just verifying. Oh well.
Now, to do the actual differential backup I ran this command:
mondoarchive -O -i -D -I "/home/bryan/Documents" -d '/mnt/home/backup3' -g -s '700m'
For backing up one little text file it still took a while because it seemed to re-generate the boot disk. I think I saw an option in the manual to not do that, but it was highly recommended that you don't use that option. Anyway, looking at the backup directory, it seems to have overwritten the full backup iso with the differential. The restore only restores the changed file (and some empty directories, hmm). So, don't save the differential in the same place as the original? How do I tell it which is the orignial backup to start from when doing the differential then?
OK, a little digging around and I discovered some emails that explain how the differential backups are done: Mondo Differential backup, Mondo Differential/Incremental BU?, and this one helped a bit too, Mondo Differential backups on two different sets. Basically, the file list and timestamp of the last backup is stored in
/var/cache/mondo-archive/, so you can specify any destination you want and it knows what to base the differential off of. I still need to try this, but my 2 year old is pulling on my away at the moment.