Serious dd breakage in current

Kevin Oberman oberman at
Mon Jan 12 16:11:17 PST 2004

Today I bit the bullet and re-sized some partitions on my laptop's
disk. One think I planned to do was copy the unchanged partitions from
my backup disk to the primary with dd(1). This was a BAD idea and I
suspect GEOM changes are at the root of it.

I used fdisk to create new slices and then bsdlabel to make new
partitions in ad0s2. Everything seemed to be fine.

Then I ran dd to copy the root partition over: dd bs=32k if=/dev/ad2s3a
of=/dev/ad0s2a For some reason it labeled the disk with the first
partition starting at almost the end of the physical partition, over 30
million blocks into the slice. bsdlabel generated a stream of errors
including that every partition extended past the physical partition.

After that, I re-did it all using dump | restore and everything went
fine, if a bit slower.

I don't recall seeing any reports of this, but it was very
unpleasant. Any ideas on what might be the culprit?
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at			Phone: +1 510 486-8634

More information about the freebsd-current mailing list