Dump Help

Alex Zbyslaw xfb52 at dial.pipex.com
Tue Nov 22 15:04:26 GMT 2005

Jean-Paul Natola wrote:

>Hi all, 
>I'm trying to utilize dump to copy the entire disc to a network  drive , so
>that in the event of hardware failure I can just restore to a new machine
>Here's the output of df
>Filesystem     Size    Used   Avail Capacity  Mounted on
>/dev/ad0s1a    248M     35M    193M    15%    /
>devfs          1.0K    1.0K      0B   100%    /dev
>/dev/ad0s1e    248M     12K    228M     0%    /tmp
>/dev/ad0s1f    4.9G    651M    3.8G    14%    /usr
>/dev/ad0s1d    248M     59M    169M    26%    /var
>devfs          1.0K    1.0K      0B   100%    /var/named/dev
>total          5.6G    745M    4.4G    14%
>here's the command I ran 
>dump / -0aL -f /usr/home/H/bsd_bkp/1116 /
>it runs well   it says  dump complete 
>but my file only turns out to be 37,314,560 bytes
>what am I missing ,  Ideally I would like ( I think I would at least) the
>WHOLE disk to be backed up....
dump, as the manual page will tell you, backs up a single partition.  
Your / *partition*:

/dev/ad0s1a    248M     35M    193M    15%    /

has only 35Mb of data so a 37Mb dump seems just right.  Now try the same for /usr, /var (and if you care) /tmp and you'll have what you want.

You might want to consider compressing those backups e.g.:

dump / -0aL -f - / | gzip -9 > /usr/home/H/bsd_bkp/1116.gz

which you can later restore with a command like:

gunzip -c /usr/home/H/bsd_bkp/1116.gz | restore -ivf -  OR restore -r  or whatever parameters suit your needs.

If you rotate your bsd_bkp dir whenever you do a full dump, you could do regular incrementals in between kept with the relevant full dumps for neatness.  Compressing will make much better use of your remote disk, and unless you have  some shrivelled up old CPU will not too slow.  If it is too slow, then a -5 or even a -1 to gzip would still make a difference, unless you have nothing but images/video/audio files.


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