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How does dump create the incremental backup? It seems I should use the same file name when I create a level 1 dump:

Full backup: 

dump -0aLuf /mnt/bkup/backup.dump /

and then for the incremental 

dump -1aLuf /mnt/bkup/backup.dump /

What happens if I dump the level 1 to a different file: 

dump -1aLuf /mnt/bkup/backup1.dump /

I am trying to understand how dump keeps track of the changes. I am using a ext3 file system.

This is my /etc/dumpdates: 

# cat /etc/dumpdates 
/dev/sda2 0 Wed Feb 13 10:55:42 2013 -0600
/dev/sda2 1 Mon Feb 18 11:41:00 2013 -0600

My level 0 for this system was around 11GB and then I ran level 1 today and I used the same filename and the size was around 5 GB.

tshepang
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1 Answers1

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I think I figured out the issue. It looks like dump adds information in the file so it knows when the previous level occurred.

Level 0 backup 

# file bkup_tmp_0_20130220 
bkup_tmp_0_20130220: new-fs dump file (little endian), This dump Wed Feb 20 14:29:31 2013,    Previous dump Wed Dec 31 18:00:00 1969, Volume 1, Level zero, type: tape header, Label my-label, Filesystem /tmp, Device /dev/sda3, Host myhostname, Flags 3

Level 1 backup, after some change 

# file bkup_tmp_1_20130220 
bkup_tmp_1_20130220: new-fs dump file (little endian), This dump Wed Feb 20 14:30:48 2013,   Previous dump Wed Feb 20 14:29:31 2013, Volume 1, Level 1, type: tape header, Label my-label,   Filesystem /tmp, Device /dev/sda3, Host myhostname, Flags 3
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