[Bug-ddrescue] ddrescue hd->tape restore from tape?

[stevecs]

Ok, I've got a large arrary disk that I'm trying to backup/restore w/
ddrescue the backup works great but since the volume is so large I have to
use many tapes to back it up (~20 LTO3's).   I'm saving off the marks / stop
points for each tape when the output volume reports as 'full' then
restarting ddrescue to pick up where it left off.   So far so good.

Question is on the restore, when I swap in/out block devices since each tape
starts at offset 0 do I even use a logfile for this or do i have to manually
set the output position based on the logs /stop points from when I did the
backup?  Ie  I'm doing this:

ddrescue /dev/md0 /dev/st0 ddrescue-md0.log

Then when each tape ends I save a copy of the log to
ddrescue-md0-<tape#>.log so I end up with a bunch of logs like
--
-rw-r--r--  1 stcost stcost   144 Oct 20 08:35 ddrescue-md0.log.aa0001
-rw-r--r--  1 stcost stcost   146 Oct 20 08:35 ddrescue-md0.log.aa0002
-rw-r--r--  1 stcost stcost   146 Oct 20 08:35 ddrescue-md0.log.aa0003
-rw-r--r--  1 stcost stcost   146 Oct 20 08:35 ddrescue-md0.log.aa0004
--
address@hidden ddrescue-scripts]$ cat ddrescue-md0.log*
# Rescue Logfile. Created by GNU ddrescue version 1.2
#      pos        size  status
0x00000000  0x273BBE70000  +
0x273BBE70000  0x34718AB0000  ?
# Rescue Logfile. Created by GNU ddrescue version 1.2
#      pos        size  status
0x00000000  0x9CDDC00000  +
0x9CDDC00000  0x51DF6D20000  ?
# Rescue Logfile. Created by GNU ddrescue version 1.2
#      pos        size  status
0x00000000  0x10239CD0000  +
0x10239CD0000  0x4B89AC50000  ?
# Rescue Logfile. Created by GNU ddrescue version 1.2
#      pos        size  status
0x00000000  0x166219F0000  +
0x166219F0000  0x454B2F30000  ?
----
When I do the restore do I need do something like (what I'm thinking):

ddrescue /dev/st0 /dev/md0 -o 0x00000000
ddrescue /dev/st0 /dev/md0 -o 0x273BBE70000
ddrescue /dev/st0 /dev/md0 -o 0x9CDDC00000
ddrescue /dev/st0 /dev/md0 -o 0x10239CD0000
...
et al?   Or is the positional data stored w/ the image so this wouldn't be
neccessary?


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