Re: [rdiff-backup-users] rdiff-backup problems (FC4 -> VFAT)

[Wiebe Cazemier]

Annoying mailinglist... It should set a reply-address so that replies go to the
list. This one is.

Bob McKay wrote:
> I originally tried this, but when I started getting all these errors, I 
> thought maybe I wasn't  excluding stuff I needed to, so decided to do it 
> instead by an 'include only if  reasonably sure it's OK' policy, which was 
> easier to do by doing separate rdiffs - with excludes, I ended up with a 
> chain of about 15 excludes, with all the attendant risks of inadvertent 
> syntax errors, overflowing command line buffers etc.
>
> I don't quite understand how rdiff-backup knows the difference between doing 
> one backup to one directory, and a number to a number of separate directories
>  in separate rdiff calls. Does it maintain a persistent global variable of 
> some sort over separate invocations? Are you certain the errors I was getting
>  were because of doing the multiple rdiffs? I was getting what appeared 
> identical errors when I did it with excludes.

I think I misunderstood you. I thought you were pointing into directories inside
an existing rdiff-backup archive, but every dir (bin, home, sbin...) is an
archive of it's own. So you're right, there should be no problem there.

BTW, you said:
> But the more important point is the unexplained errors subsequently, which 
> seem to reflect problems with the backup. When I try to re-run rdiff-backup, 
> it complains that, eg:

That's not more or less important than your first error. It just says that the
first time went wrong.

And:
> I'm not sure why rdiff-backup thinks it is unable to handle access control 
> lists, since posix1e.so seems to be in the right place?

You are sure you have ACL's? If so, perhaps it has something to do with it being
a LVM. I don't have much experience with ACL's, so I can't help there.

I am kind of confused about the errors you're getting BTW. It's not very clear
which error, if any, is the fatal error. They're most warnings and ingored 
errors.

When you backup to a non-FAT32 filesystem, what happens then?

> I guess I wasn't careful enough in my explanation. I certainly have a number 
> of bongled config files etc that I do need to back up, and a number of 
> installed utilities. I could probably get away with just /etc and /usr; but I
>  included /bin, /sbin etc just to be on the safe side, on the basis that 
> they're not that big, and don't change that often, so the extra backup cost 
> was minimal - and if I turn out to be wrong in this, it's easy enough to 
> remove them later.

Restoring an application by copying the files from /bin etc is not a good idea.
You need to install software through the package manager, or you won't be able
to keep track of what is installed. When just copying files, you end up with a
system you have to reïnstall eventually.

> Hmmmm, the former's a rather nasty problem I hadn't thought of. The latter 
> probably doesn't matter much. It's not my intention to restore the system 
> from backups - as I said, I would do a clean install; the intention of 
> including "all but the kitchen sink" in the backup was to be absolutely 
> certain I wouldn't subsequently discover I had omitted a critical config file
>  or updated binary. I'm prepared to pay a couple of extra gigs of infrequent 
> backup over an IDE bus for that peace of mind. If I was more expert in unix 
> system admin, I'd get my peace of mind from knowledge about what I could 
> safely exclude; since I don't have that, or the time to get it, better safe 
> than sorry.

Backing up to another HD poses the same kinds of problem mentioned earlier. When
using "cp", make sure you use "-a" to keep all the properties intact. And, when
restoring, don't restore parts of the backup into an existing system, for the
same maintainability issue as mentioned above.

If you do want to make system backups to removable media in the future, I
recommend Dar (http://dar.linux.free.fr/). It provides everthing you can think
of when doing backups.

Also, you might want to put RAID1 in your computer. Not really hard to do, with
Linux software RAID. Software RAID is better than those RAID controllers on
mainboards BTW. So, unless you have a real hardware RAID card, use software.