Yesterday I had to restore my system out of an lvm snapshot backup created with cpio

cpio -idv --no-absolute-filenames < ${backup_file}

I allready used those backups for different restore operations - but not for the root filesystem itself. What happend to me was that the cpio version provided by the rescue system wasn't able to preserve the directory permission.

Original:

root@mephisto /var/spool/postfix # l
total 76
drwx------  2 postfix root     4096 2010-06-03 10:55 active/
drwx------  2 postfix root     4096 2010-06-03 09:18 bounce/
drwx------  2 postfix root     4096 2010-05-18 12:34 corrupt/
drwx------ 17 postfix root     4096 2010-06-01 08:40 defer/
drwx------ 17 postfix root     4096 2010-06-01 08:40 deferred/
[...]

After restore:

root@mephisto ...ckup/mnt/root_backup/var/spool/postfix # l
total 76
drwx------  2 postfix root     4096 2010-06-03 11:02 active/
drwx------  2 postfix root     4096 2010-06-03 11:02 bounce/
drwx------  2 postfix root     4096 2010-06-03 11:02 corrupt/
drwxr-xr-x 17 root    root     4096 2010-06-03 11:02 defer/
drwxr-xr-x 17 root    root     4096 2010-06-03 11:02 deferred/
[...]

So my suggestion - don't use cpio! Use tar instead.