Re: [BackupPC-users] copy pool to another filesystem formatted differently

[Daniel B. <da...@fi...>]

Le Fri, 28 Sep 2007 20:00:49 -0600,
Ben Nickell <twi...@ph...> a =C3=A9crit :

> I have set up my new backuppc filesystem on an LVM volume and decided
> on using ext3 for the filesytem.  The old filesytem is reiserfs.
> I would like to copy the old filesystem to the new larger volume.
> The backuppc FAQ states:
>=20
>     The best way to copy a pool file system, if possible, is by
> copying the raw device at the block level (eg: using dd). Application
> level programs that understand hardlinks include the GNU cp program
> with the -a option and rsync -H. However, the large number of
> hardlinks in the pool will make the memory usage large and the copy
> very slow. Don't forget to stop BackupPC while the copy runs.
>=20
>=20
> At the risk of exposing my ignorance, If I use dd won't it copy=20
> filesystem information as well?   Maybe I'm just tired and not
> thinking clearly. but would something like this work?
>=20
> dd if=3D/var/mapper/vg-reiserfs_volume
> of=3D/var/mapper/vg-larger_ext3volume
>=20
> I know that rsync would take a really long time.  (about 1.1tb of
> data, with all the hardlinks)  Should I just try cp -a?
>=20
> Any other suggestions?
>=20
> Thanks,
> Ben

To move the pool, I use rsync to transfert everything excluding the
directory "pc" (which contains all the hard links, so the others
directory can be transfered with rsync -avP or something like that).

Then I use the script BackupPC_tarPCCopy which is part of BackupPC 3.0.
This script write a raw tar archive on the standard output which
contains all the pc directory (or just a part, depending on what you
want). I just pipe this output in another tar command which will
extract on the fly to the destination I want.

It will give something like that:

BackupPC_tarPCCopy /path/to/data/dir/pc | (cd /destination/pc && tar xPf -)

It's not very fast, but it works. ANd you can also use something like that
to send the pool to a remote host: you just have to pipe the output of
BackupPC_tarPCCopy to ssh like this:

BackupPC_tarPCCopy /path/to/data/dir/pc | ssh remoteuser@remotehost "(cd /d=
estination/pc && tar xPf -)"

You can also compress on-the-fly the archive:

BackupPC_tarPCCopy /path/to/data/dir/pc | gzip -c | ssh remoteuser@remoteho=
st "(cd /destination/pc && tar xzPf -)"


But for a 1.1 TB, I'm not sure how many time it will take.

Cheers, daniel