Re: Copy a tape with a single drive...

> I've still two question.

More question rised.

Seems that, even using a temporary file media, copy is more performative
then a full backup.

For example, on a test system with an LTO5 tape, full backup took 14 hour,
while copy tape to file media took 4 hour, and file back to tape 3 hour; so,
more or less, half time.

To make the tape->disk phase as just stated i've used:

	bcopy LTO5Storage FileStorage -i PPPVE3_0001 -o PPPVE3LTOCopy_0001 -b /tmp/FVG-PP-PPPVE3.bsr

with the bootstrap file copied from the director. 'PPPVE3LTOCopy_0001' is a
file volume on a pool used only for that; i've created in bacula configs all
the stuff needed (eg: storage, pool; and labeled the volume).


To copy back the data i've instead labeled by hand a new tape with:

	echo -e "label\nPPPVE3_0001_COPY\n" | btape /dev/nst0

and then copy back data with:

	bcopy FileStorage LTO5Storage -i PPPVE3LTOCopy_0001

so it is not needed to specify bootstrap file and destination media if
destinationn device is a tape. Instead, it IS needed to specify it if it is
an input.
I suppose i can label the 'copy tape' exactly the same of the original tape,
but because it is not an 1:1 copy of the original (see next point) seems to
me 'confusing' (eg, bootstrap file will not match on copied tape, i suppose).

I've also tried with 'bls' to scan tape content, and all file seems there.
So, copy seems effective. Good.


This was a test system; in a production one i've multiple backup jobs that
go to the tape, so specifying a bootstrap file i suppose i copy only that
jobs, not all jobs on tape; i supposed that because data on tape was roughly
9TB, while the file media:

	root@svpve3:~# ls -lah /rpool-backup/bacula/SVPVE3LTOCopy_0001 
	-rw-r----- 1 bacula tape 3.9T Feb 20 19:41 /rpool-backup/bacula/SVPVE3LTOCopy_0001

also, i've tried to scan with 'bls -j' the media, and i found only job
session records of that backup.


So, a 'bacula tape copy machine' will have to, theoretically:

 + for every job in tape:
   - copy bootstrap file from director for that job
   - dump that jobs in tape to disk volume
   - dump disk volume to 'copy tape'
   - purge and truncate disk volume
   - repeat

...seems pretty complex and error-prone...

--