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bug#17149: shred - tape data
From: |
Pádraig Brady |
Subject: |
bug#17149: shred - tape data |
Date: |
Mon, 31 Mar 2014 18:32:32 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 |
On 03/31/2014 12:00 PM, Rupert Russell wrote:
> Hi,
>
> shred -v /dev/st0 # where /dev/st0 is the drive in a multi tape carousel.
>
> This starts well with.
> Pass 1/4 (random) 15MiB
> Pass 1/4 (random) 41MiB
> Pass 1/4 (random) 70MiB
> Pass 1/4 (random).....etc
>
> But when the end of a 200GiB tape is reached in pass 1, 'shred' doesn't
> appear to trigger a rewind or maybe wait for the tape to be rewound before
> attempting to overwrite the data.
>
>
> The final messages before and around the error are:-
>
> Pass 1/4 (random) 190GiB/190GiB 100%
>
> Pass 2/4 (random)
>
> Error writing at offset 1288. No space left on device.
>
> (The next line in my script then runs and unloads the tape.)
>
> Is this not rewinding the tape a bug or my mis-use of the 'shred' command?
shred(1) doesn't rewind the tape.
It could issue an MTREW ioctl or something,
though I suspect there are all sorts of ioctls to consider depending on
plaftorm.
I also see the `mt erase` command/ioctl which might suffice?
If not then explicitly handling the tape like this might suffice?
for i in $(seq 3); do
mt -f /dev/st0 rewind
shred -n1 /dev/st0
done
thanks,
Pádraig.