Originally posted by: jenlmead

Hey AIXers,

I am trying to compile disk scrub provided by Google for scrubbing data from AIX disks. Supposedly it compiles, but I haven't had any luck doing that. Has anyone else? Or do you know of an already compiled version out there? Or do you know of any other tool that works? I am stumped.

Jen
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Originally posted by: dukessd

Hi Jen,

AIX already has a tool to do this and if you need to scrub the whole system including rootvg then you can download the AIX diagnostic boot CD ISO and then boot from this and use the same utility to scrub all of the hdisks.

From AIX as root:
Diag
Task Selection
Format Media
Select disk, F7 to continue
Erase Disk
Enter to continue
YES to continue
Write patterns to drive

3 random patterns should be fairly safe but use more if you want, I think DoD specify 7.

The Diag CD ISO download:
http://www14.software.ibm.com/webapp/set2/sas/f/diags/download/home.html
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Originally posted by: jenlmead

Okay, I will look into that for an option. I got the scrub software to compile on 5.8, wouldn't do it on 6.1 but I am able to copy the binary there and it runs fine. However, I started to scrub a 20G drive yesterday before I left work and it still isn't done. LOL. Geesh. Thanks for the suggestion, I will try it today and check the timing.
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Originally posted by: jenlmead

Well I am just blown away about how long this activity takes. I sat up a box as a nim client and told it to use a spot, then booted the box on the network and it came up with the desired disk erase feature that I was hoping for. However it has been running for 3 hours with no end in sight. This is a 20G disk! Sigh. Any other suggestions out there?
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Originally posted by: dukessd

Drill a hole in the disk.
The hole will put the disk off balance so it will vibrate and the heads will not be able to track the data and the resulting swarf will also ruin the disk surface.

Either that or go at it with a big hammer.

;-)
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Originally posted by: MarkTaylor

I am sure I have compiled scrub on AIX without any issues, why not paste your compile command and errors ..

Rgds
Mark Taylor
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Originally posted by: jenlmead

Oh I know how to destroy discs, that is not the problem. We are doing a DR test at SunGard and the discs are actually 3000 miles away from where our test is taking place. We have no access to any hardware (not that they would let us destroy their discs anyway).
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Originally posted by: dukessd

OK, drilling a hole in the disk will obviously pose logistical problems then, long way to drive or an unfeasibly long drill bit.

Can you nim boot the node into a maintenance shell and then use diags to trash the disks?

It would save all this "disk scrub" nonsense.
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Originally posted by: j.gann

the popular myth "overwrite N times" (possibly with different bitmasks) has been scientifically examined last year with the result that a single overwrite is enough to yield data on a harddisk unrecoverable.

your flexible friend dd if=/dev/zero will do.

cheers
Joachim
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Originally posted by: Kosala

I agree with you but, not with /dev/zero. I once read a research paper which describes the disadvantages of writing zeros, opposed to writing ones. Unfortunately there is no pseudo device to generate ones in UNIX (AFAIK).

Yet reading the ghost magnetic image out of a HDD will require well funded hacking, not possible with average funded hackers. Considering this, writing random bit patterns will be more agreeable.

Kosala
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Originally posted by: jenlmead

Thanks everyone for your input. I appreciate it.

Jen
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