SCSI Shock Advice !

Jerry McAllister jerrymc at clunix.cl.msu.edu
Tue Sep 21 07:46:18 PDT 2004


Hi,

> Thanks for replies, however I need advise
> on cloning the IDE to the SCSI disc.
> 
> G4U did not finish correctly and once
> I had made changes to fstab and booted
> the fs I got some pretty severe errors.
> 
> /usr was inaccessible and I ended up 
> using Freesbie to re-edit fstab to get
> a booting system.
> 
> I think the problem is that the SCSI
> disc is 38GB (only 1.7GB used) and
> the IDE is 40GB.
> 
> What is the best / safest way to do
> a disk clone in this case?

Don't use any of the cloning utilities (not even dd) because you 
are not trying to make an exact byte for byte clone, but rather
a functional copy.   That is quite different.

The best thing is to create the new file systems
eg slice (fdisk) partition (disklabel or bsdlabel in 5.xxx) 
and build the file system (newfs) and then mount the new file
systems to a temporary mount mount and  transfer each file system 
separately by running dump and restore.

Note:  To make a bootable copy you will need to put in an MBR when
you do the fdisk to create the slice and a boot block when you do t
the disklabel/bsdlabel when you do the partitioning.  Don't leave 
those out.

If you have room, you can run a dump to a file in spare space
somewhere and then  restore from that file.  If you don't have 
the extra space, you can pipe a dump of the old fs to a restore
to the new one.  Make sure you cd in to the new file system 
before doing the restore whichever way you are doing it.

This is covered pretty much in the man pages of dump and restore.
But, say your SCSI is da0 and you created one slice and did the
label/partitioning ok and newfs-ed all the partitions and now you
want to put the old root on the new disk.

  cd /
  mkdir newroot
  mount /dev/da0s1a /newroot
  cd /newroot
  dump 0af - / | restore rf -

Do the similar for each of the file systems you want/need to move over.
That probably means all of them.

When you are done, the only thing left to do, besides checking things
out to make sure they look good is to modify the new copy of /etc/fstab
so the devices to mount will now be da0s1..  instead of ad0s1..

You can also get rid of all the 'restoresymtable' files in each
new filesystem.  Restore uses those to keep track of itself and they
are no longer needed once it has successfully completed.

You should then be able to shuffle any disks and bios you need to
to make the SCSI disk the boot device and then boot and run.

////jerry

> 
> Thanks again
> 
> Graham
> 
> 
> Custom PC North West
> Open Source Solutions
> http://www.cpcnw.co.uk
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