[lug] Backup to 2nd HD with dd & rsync?

[Peter Hutnick]

Nate Duehr said:

> SCSI handles the MBR differently with the whole initial ramdisk
> (mkinitrd) thing... the IDE probably won't boot properly after a dd from
> the SCSI, but never tried it.

The initial RAM disk adn SCSI aren't related in any technical way.  You
probably have the impression that they are because distro kernels tend to
have IDE support built in and SCSI support as modules on an initial RAM
disk image.  This is because any given SCSI driver is far less common than
the IDE driver.  IOW this relates to packaging, not how the kernel works.

As to making a backup, I have done this with rsync from one IDE disk to
another IDE disk of a different type.  Using dd is likely to cause far
more problems than it solves for this task.  If you want true backups try
dump.  If you want what I call a "cold mirror" run rsync out of cron.

One system I set up this way excluded /etc/fstab on the backup.  I set up
a floppy and rdeved it to the backup drive.  I manually edited the backup
copy of /etc/fstab.  That floppy could then be used to roll the system
back to the last rsync.

The nice thing about this is that it is very easy to recover a file from
the rsync backup; just mount the disk and use normal filesystem tools
(i.e. cp).  Beats the hell out of tapes for an "oops" type restore.

-Peter