Quantum tape drive
Dan Nelson
dnelson at allantgroup.com
Wed Jan 28 13:49:46 PST 2009
In the last episode (Jan 28), Jaime said:
> On Wed, Jan 28, 2009 at 3:23 PM, Dan Nelson <dnelson at allantgroup.com> wrote:
> >
> > In the last episode (Jan 28), Jaime said:
> >> /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.
>
> Thanks. Would this decrease the ability of other Unixes being able to
> read the tape? For example, using pax (which can read tar archives)
> or GNU's tar?
It shouldn't. At worst you may have to specify a matching blocksize
argument when reading.
> Sadly, I forgot to mention something in my last message. Sorry.
>
> When reading from the tape using tar (bsdtar from FreeBSD 6.2 -- and,
> yes, I'm preparing a cvsup as I write this :) ) the tape drive's Alarm
> and Fault LEDs are lit up and then camcontrol devlist no longer shows
> the tape drive.
According to
http://downloads.quantum.com/dlt_v4/DLT-V4_Product_Manual_81-81422-03_A01.pdf#page=67
, there is no alarm LED on a DLT-V4 drive, just Ready, Fault, Clean, and
Media. If the Fault light is lit solid, it says that's an "Internal
firmware error". If Fault and Clean are blinking slowly, you may have a bad
tape or may need to put a cleaning tape in.
> After I wrote to the tape via a quick boot into Knoppix, I found that
> FreeBSD's tar command could list the files on the tape. So maybe that is
> in the past now. Maybe not. I should have mentioned it earlier. Sorry.
>
> Any other thoughts before I try to OS update and the larger block size?
--
Dan Nelson
dnelson at allantgroup.com
More information about the freebsd-questions
mailing list