Hi! For my dentist I'm currently in the process of destroying some tape cartridges (SLR7) and also two hard disks (147G SCSI). As I started for the tapes, I've used dd to fill the tape with random garbage. Just a simple `dd if=/dev/random of=/dev/nsa0'. The tape sits there since 48 hours writing a block of data every other minute and still didn't fill up the tape completely. The system this is running on is a P-4 3GHz machine using FreeSBIE 2.0 (6.2-RELEASE based). I suspect this to be a slow /dev/random. Is there any chance to speed up /dev/random? Would a hifn accelerator card help here to get FreeBSD produce garbage faster? As there is medical data on all media I really need garbage (/dev/zero wouldn't be enough for data security as this might get recovered). Thx, Volker
On Mon, Feb 19, 2007 at 08:40:37PM +0100, Volker wrote:> Hi! > > For my dentist I'm currently in the process of destroying some tape > cartridges (SLR7) and also two hard disks (147G SCSI). > > As I started for the tapes, I've used dd to fill the tape with > random garbage. Just a simple `dd if=/dev/random of=/dev/nsa0'. > > The tape sits there since 48 hours writing a block of data every > other minute and still didn't fill up the tape completely. The > system this is running on is a P-4 3GHz machine using FreeSBIE 2.0 > (6.2-RELEASE based). > > I suspect this to be a slow /dev/random.This sounds odd to me, I get 18-20MB/sec sustained read performance from /dev/random on this 2GHz system, which is probably faster than your tape write speed.> Is there any chance to speed up /dev/random? Would a hifn > accelerator card help here to get FreeBSD produce garbage faster? > > As there is medical data on all media I really need garbage > (/dev/zero wouldn't be enough for data security as this might get > recovered).Neither would a single pass with /dev/random, but you presumably knew this. Kris
Volker wrote:> Hi! > > For my dentist I'm currently in the process of destroying some tape > cartridges (SLR7) and also two hard disks (147G SCSI).The obvious question - why don't you burn the tapes and hammer the disks? :)
On Mon, 19 Feb 2007, Volker wrote:> For my dentist I'm currently in the process of destroying some tape > cartridges (SLR7) and also two hard disks (147G SCSI). > > The tape sits there since 48 hours writing a block of data every > other minute and still didn't fill up the tape completely. The > system this is running on is a P-4 3GHz machine using FreeSBIE 2.0 > (6.2-RELEASE based). > > I suspect this to be a slow /dev/random. > > As there is medical data on all media I really need garbage > (/dev/zero wouldn't be enough for data security as this might get > recovered). >As a quick (slow?) fix, couldn't you just fill the disks with random data and then dump that data to your tapes? /Chris -- www.infotropic.com
Volker wrote:> For my dentist I'm currently in the process of destroying some tape > cartridges (SLR7) and also two hard disks (147G SCSI).[snipped]> Is there any chance to speed up /dev/random? Would a hifn > accelerator card help here to get FreeBSD produce garbage faster? > > As there is medical data on all media I really need garbage > (/dev/zero wouldn't be enough for data security as this might get > recovered).You could use DBAN [0] to wipe the data, at least on the disks ;) That also takes some time (depends on the method you choose) but it's worth it... HTH, Philipp [0] http://dban.sourceforge.net/ -- www.familie-ost.info/~pj
Volker <volker@vwsoft.com> wrote:
> For my dentist I'm currently in the process of destroying some tape
> cartridges (SLR7) and also two hard disks (147G SCSI).
The most secure and fastest way (by far) is to burn the
tapes, and to open the hard disk cases and apply some
sandpaper to the disk surfaces. (Contrary to popular
believe, a huge magnet might not be sufficient.)
Best regards
Oliver
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Ivan Voras wrote:> The obvious question - why don't you burn the tapes and hammer the disks? :)Ah, low-tech. I know it well. Still, the last time I did any data destruction, I found a 4 Tesla magnet does wonders. Downsides: 1) Oxford's 90cm bore, helium-cooled magnets aren't that common, perhaps because a 2000V/500A power source is a bit expensive (solution doesn't scale). 2) The hard drive has a tendency to fly out of one's hands while moving it through the lines of force (solution requires some physical coordination). It's primarily for item #1 that I hadn't mentioned this earlier, as most readers of -STABLE users are probably looking for a more scalable solution. -- Alan Amesbury University of Minnesota