Re: Backing up a Debian system
On Sat, Aug 03, 2002 at 12:28:53PM -0500, Drew Scott Daniels wrote:
> On Sat, 3 Aug 2002, Matt Zimmerman wrote:
> > The point was that the status database contains other information, in
> > addition to the selections, which is vital for a proper restore. E.g., the
> > version number of the installed package.
> >
> > In fact, I would say that the entire /var/lib/dpkg hierarchy would not be
> > too much to backup. This would ensure that statoverrides, diversions, and
> > data for similar future mechanisms can be restored.
> >
> Wouldn't just restoring /var/lib/dpkg cause inconsistency problems under
> /var/cache/apt ? I would worry about not having the specific package
> versions available unless they were in stable. Packages in stable don't
> change much, but when they do, it's usually for a very good reason and thus
> beneficial to upgrade.
/var/lib/dpkg could not be restored in its entirety, no. But the
information contained in it would be used to reconstruct the system
(particularly installed package versions).
> My personal preference is to get the latest package anyway. I thus
> wouldn't backup the packages, their files (other than config and custom
> files) and also their versions. But I can see having the package version
> being backed up as being useful to some users and that's why I'm asking
> more.
If I want the latest package, I upgrade. If I am running software that is
older than what is available in the archive, it is for a good reason (the
package is probably on hold, or I am deliberately not upgrading it). This
is especially true when tracking testing/unstable for certain packages,
since the installed version could disappear relatively soon.
In general, a backup/restore should not change the versions of installed
software. This can introduce unexpected changes, something which should
definitely be avoided during a restore. The system should be brought back
as close as possible to its state at the time of the backup, in terms of
functionality. Things like file access times can be lost, of course.
But packages should stay at the same version.
--
- mdz
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