A snapshot of your computer with dd, pv and gzip - Part 1
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A snapshot of your computer with dd, pv and gzip - Part 1
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Re: A snapshot of your computer with dd, pv and gzip - Part 1
#2Just by the by, this is a terrible idea to do online. The best case is a crash-consistent replica. The more likely case is an inconsistent one that may or may not be repairable, because of the length of time it takes to do the dump.
If you want a bit-for-bit dump of an online filesystem, use Linux LVM to create a snapshot, then make an image of that (100% known crash-consistent) copy.
Re: A snapshot of your computer with dd, pv and gzip - Part 1
#3If you want to backup with this kind of technique, use partimage instead, and do so from a rescue CD. You need a quiescent filesystem for imaging, so it can't be under use by the running OS.
Re: A snapshot of your computer with dd, pv and gzip - Part 1
#4Hmm, I'm a bit wary of this kind of backup, because it seems like it's nontrivial to recover part of your data if half of the backup goes bad. While the old fashioned rsync/copy all your files may be less efficient, you'll still have whatever it managed to copy if something goes wrong partway through.
This reminds be of doing a tar archive of all your files--if the archive is corrupted during that process, what then?
Re: A snapshot of your computer with dd, pv and gzip - Part 1
#5At first glance it reminded me of this counter argument which warns about using `dd`, especially on a failing drive.
Re: A snapshot of your computer with dd, pv and gzip - Part 1
#6Consider using Clonezilla [1] instead. While dd will produce a sector-by-sector image of your medium (which can be terribly inefficient if you're using considerably less than 100% of its available space) Clonezilla is file system-aware for a number of common file systems and has built-in support for compression as well. It resembles the recently discontinued Norton Ghost this way but is fully FOSS.
I normally run it off a live CD/USB of Parted Magic [2], another tool I can wholeheartedly recommend.
Re: A snapshot of your computer with dd, pv and gzip - Part 1
#7On OSX, CarbonCopyCloner works really well :)
Re: A snapshot of your computer with dd, pv and gzip - Part 1
#8Consider using Clonezilla [1] instead. While dd will produce a sector-by-sector image of your medium (which can be terribly inefficient if you're using considerably less than 100% of its available space) Clonezilla is file system-aware for a number of common file systems and has built-in support for compression as well. It resembles the recently discontinued Norton Ghost this way but is fully FOSS. I normally run it…
I'd also recommend SysRescueCD that has these types of tools ready to be used as a bootable USB/CDrom image.
http://www.sysresccd.org/System-tools
I've used the imaging tools on the boot cd a few times to clone/restore hosts a few times without any issues. Very handy.
Re: A snapshot of your computer with dd, pv and gzip - Part 1
#9Consider using Clonezilla [1] instead. While dd will produce a sector-by-sector image of your medium (which can be terribly inefficient if you're using considerably less than 100% of its available space) Clonezilla is file system-aware for a number of common file systems and has built-in support for compression as well. It resembles the recently discontinued Norton Ghost this way but is fully FOSS. I normally run it…
I second the Clonezilla recommendation. Clonezilla is a monumental set of bash scripts that act as a "wizard" to drive a number of other programs. The most important one is probably partclone. You don't have to use Clonezilla to use partclone (it's packaged in linux distributions like Debian), but Clonezilla makes it easier.
Re: A snapshot of your computer with dd, pv and gzip - Part 1
#10If you want to backup with this kind of technique, use partimage instead, and do so from a rescue CD. You need a quiescent filesystem for imaging, so it can't be under use by the running OS.
Partimag development has been dead for years; take a look at partclone instead. Another program with a similar goal but a different approach is FSArchiver.