Copying a large file system (again)

[Tino Schwarze]

On Mon, Dec 03, 2007 at 11:51:40AM -0500, Tom Rockwell wrote:

> How about breaking the rsync into steps --- instead of doing the whole 
> directory tree at once, do the top level or two manually and then fill 
> in the branches in a few or several chunks.

Well, that's not possible with the BackupPC layout - there are hardlinks
all over the place. The basic structure of a BackupPC pool is as
follows:

/backup/backuppc/pool/
contains subdirectories 0/1/2/3/
and files therein (with md5sum-names): 01234567890ABCDEF...

/backup/backuppc/pc/server1/0/
contains Backup 0 of serer1, files hardlinked to the pool.
/backup/backuppc/pc/server1/5/
contains Backup 5 of serer1, files hardlinked to the pool.
/backup/backuppc/pc/server2/10/
contains Backup 10 of serer2, files hardlinked to the pool.

So I cannot split the whole transfer into pieces since that would loose
hardlinks, therefore the required space on disk would explode (the pool
effectively holds over 2 TB while requiring only about 550 GB on disk
because of the hardlinking scheme).

I need to copy the whole /backup/backuppc directory structure in one
pass so that hardlinks are preserved. Or I'd need some tool which could
preserve the hardlinks another way.

Bye,

Tino.

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