Quantum tape drive

Dan Nelson dnelson at allantgroup.com
Wed Jan 28 12:23:54 PST 2009


In the last episode (Jan 28), Jaime said:
> I am trying to replace an older DLT tape drive (which doesn't like to
> eject tapes any more) with a new Quantum DLT-4 drive.  Its connected
> by internal SCSI and seems to be set up right.  But after DAYS of
> running a tar command, its still not done backing up 60GB.  The old
> drive could backup 70-80GB in about 7 hours.
> 
> Any suggestions?
> 
> 	/usr/bin/tar -cvpX /usr/local/etc/backups/skiplist-relative.txt -f /dev/sa0 -C / .

If nothing else, I suggest bumping up your blocksize.  The default for tar
(10k) is pretty small for modern tape drives.  Try -b 128 (for a 64k block
size).  Another optimization would be to put a buffering program in between
tar and your tape drive to decouple disk reads from tape writes.  misc/team,
misc/buffer, and misc/cstream in ports are good for this.

-- 
	Dan Nelson
	dnelson at allantgroup.com


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