Backup complete gmirror/gstripe/gjournal drives, how-to?

Ivan Voras ivoras at
Mon Dec 8 08:22:07 PST 2008

2008/12/8 Doug Poland <doug at>:
> On Mon, Dec 08, 2008 at 10:29:36AM +0100, Ivan Voras wrote:

>> I hope you understand the problems with this kind of backup
>> procedures.
> Actually, I don't, that's why I'm posting :)  My intent is to have a

Here are a couple of things:

a) How do you intend to restore the images? You need drives with >=
size of the original drives (and images). If you have larger drives,
the extra space might be wasted.
b) With this method you cannot use (or actually, you can but it's very
hard) any kind of differential/incremental backup, and in addition to
the used space you're also backuping the unused/"empty" space.
c) dd as you've used it will skip bad sectors, in a bad way - it will
either stop (according to the documentation) or concatenate data
blocks around the ones containing the bad sector (e.g. if a sector in
the tenth block of 2 MB is bad, your file will contain blocks
...8,9,11,12,...). See conv=noerror,sync options to dd.

More information about the freebsd-questions mailing list