[conspire] How do I determine what I need to keep from my internal hard drive and what is the recommend way to move things to an external hard drive

Rick Moen rick at linuxmafia.com
Wed Sep 8 17:58:23 PDT 2010


Quoting Darlene Wallach (freepalestin at dslextreme.com):

> Thank you - I'm using the rsync command with the 'z' option too.

As Nick said, the 'z' option makes sense only when you're moving files
across slow links, such that the reduced transmission time warrants the
large gzip/gunzip CPU/RAM overhead.  It makes no sense when moving files
locally across fast mass-storage buses.

> > 2.  Snapshot of your partition layout.
> I used "parted -l" since I used parted to create the partitions. I
> like the naming scheme of including the date.

Yeah, 'fdisk -l', 'parted -l', whatever.  I'll have more to say about
Nick's 'You shouldn't bother with this because you shouldn't bother with
partitioning beyond the minimal' reasoning when I have time.


> Now my question is:
> What is the recommend way to get a snapshot of my installed Fedora,
> which currently is Fedora-10? My reason for the question is I
> attempted to install Fedora 11 a while back but the temporary user
> login was not generated and I could not login so I went back and
> reinstalled Fedora 10. In the future if an install fails, I'd like to
> be able to get back to my previously installed system. Would I use
> genisoimage? Then if I needed to I could use that .iso copy it back
> onto my internal hard drive and get my system back?

Fundamentally, I am philosophically opposed to the 'take a picture of
the entire system' approach to backups.  I know it's popular, but
strongly suspect its popularity is just a side-effect of people not
understanding their systems and therefore lacking confidence that they
know what elements of the current system are worth capturing and which
are not.  That is, they fear that they will do a system restore and only
then discover that something important is missing.  So, they compensate
by snapshotting tens of gigabytes of things that don't matter because,
e.g., those things could be provided automatically by the distro package
system.

My idea of how to solve the ignorance-of-systems problem is a radical
(i.e., going to the root of the problem) one:  If you're not sure you
have captured all the parts of your system that matter, then find out.
Do a restore, and see if everything that matters is there.  How do you
know everything that matters is there?  The functional test is:  If you
don't miss it, then it must not have mattered.

The 'Backup Scheme' link on http://linuxmafia.com/kb/Admin/ is one
that's already passed the functional test -- at least, for me and for my
server system.  Further, it passes the functional test in ways in which
'take a picture of the entire system' schemes are in essence somewhat
deficient:

Let's say I last used a 'picture of the entire system' scheme such as
Mondo Rescue (http://www.mondorescue.org/) to cut a full system image to
DVD in June 2010.  Let's say that, in September 2010, I either suffered
HD failure or for some other reason needed to rebuild.

What results is that I'll get June 2010 versions of all installed
software.  Well, that mildly sucks.  It's September:  Wouldn't it be
better to get the September versions?

The method described on the 'Backup Scheme' link accomplishes that. 
Instead of snapshotting everything, it captures to an ASCII file a
roster of _package names_ for all installed packages.  When my system
hypothetically gets bollixed in September, the rebuild method involves
feeding that roster to dpkg, which installs _current_ (September)
versions of everything.

And my backup sets are inherently _way_ smaller than any 'picture of the
entire system' set.


But, anyway, one answer to your question as posed, even though I
fundamentally dislike that method of operation, is 'Use Mondo Rescue'.






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