From: Ray Todd Stevens <raytodd@ki...> - 2008-12-24 03:03:00
Interesting. First the tar thing definitely did not work.
Second it sure might be good to have this in the documentation. It might be even cooler to
have a restore from tape function as a part of the application.
> Ray Todd Stevens wrote:
> > OK I have the system so that I can save an archive off to tape. (select
> > the tape host -> start an archive --> select the hosts to be archived
> > --> press the start button at the bottom of the page)
> > But if and when I need to recover the data that is on that tape how do I
> > do that?
> You'll end up with a normal tar archive, so the restore would be the same
> as if you had created a tar tape directly.
> > After all a backup is only as good as the restore procedure.
> You can use something like 'tar -tv /dev/tape' to check the tape files,
> -xv to copy them into your current directory. Add 'z' if you used
> compression - you might need a blocking factor, depending on the tape
> type. In a real disaster scenario you'll work from a bootable CD or do
> enough of a system install to have the tape working and a place to drop
> the files. Note that if you still have access to the backuppc server you
> can also run Backuppc_tarCreate via ssh to get a tar stream over the
> network instead.
> I've never put more than one host on a tape so I'm not sure what is
> involved in separating them if you do.
> Les Mikesell
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From: Les Mikesell <lesmikesell@gm...> - 2008-12-24 18:57:03
Ray Todd Stevens wrote:
> Interesting. First the tar thing definitely did not work.
Can you write a tar tape directly to the device and read it back? Tar
normally writes (and reads) in 10k blocks and many tape devices are
sensitive to the block size in that accesses must match or be an exact
multiple of the block size set with 'mt' and the read size must match
the size of the write for the same data. I don't think backuppc deals
with blocking at all, so if you need it and have intermediate space you
might write to a file instead, then later copy it to tape with dd using
obs=10k as an option. Or just generate the tar image with the command
line tool BackupPC_tarCreate and pipe through dd to get the obs=10k
option as you write to tape.
> Second it sure might be good to have this in the documentation.
It is very much operating system and hardware dependent.
> It might be even cooler to
> have a restore from tape function as a part of the application.
Most of the point of making an archive in tar format is that you don't
need a special application to restore it. Any copy of tar should be
able to extract the files. If you have backuppc running, most of the
time you would want to restore directly from its disk copy.