destroying data on disks while decomissioning a server

[Jay Cantwell]

I need to destroy data on my data disks on a system we are shutting down. I am using the procedures listed in KBRC00005001. I have one question, does the mount point need to be unmounted and does the vg need to be deactiviated before the mediainit ?

thanks...Jay

[Pete Randall · Accepted solution]

Since mediainit uses the path name of the raw device, I don't think it would be necessary to unmount/deactivate, but, by the same token, I think it would be neater and cleaner if you did.


Pete

[Raj D.]

Hi Jay ,

Here is something that can help to destroy data for decommission purpose:

1.
# dd if=/dev/zero of=/dev/rdsk/c?t?d? bs=1024

Also you can use :
2.
# pvcreate -f /dev/rdsk/c#t#d#

3.
And Mediainit can be use directly.


Cheers,
Raj.

[Raj D.]

Hi Jay ,

Also find this doc ,attached is a description of how to use Ignite-UX to scrub disks :


Hope this will also help..
Cheers,
Raj.

[Sยภเl Kย๓คг]

Hi,
You can very well use the pvcreate with -f option to distroy the data, and is very simple and less time consuming way.

make simple script like one whihc is bellow to perform the activity.

#Script for distroying data
for i in `vgdisplay|grep "VG Name"|awk '{print $3}'|grep -v vg00`
do
for j in `vgdisplay -v /dev/vg_sbt_fone_appl|grep -v "Alternate Link"|grep "PV Name""|awk '{print $3}'
do
pvcreate -f $j
done
done

Regards,
Sunil

[Sยภเl Kย๓คг]

Sorry a small corruction in the script

#Script for distroying data
for i in `vgdisplay|grep "VG Name"|awk '{print $3}'|grep -v vg00`
do
for j in `vgdisplay -v $i|grep -v "Alternate Link"|grep "PV Name""|awk '{print $3}'
do
pvcreate -f $j
done
done

Regards,
Sunil

[A. Clay Stephenson]

Pvcreate is an extremely poor choice for this task. It will only affect the VGRA -- a very small fraction of the usable disk space. You can convince yourself of this by writing a large file containing lists of data something like "This is a test nnnnn". Next run pvcreate on the disk and then read every block of the raw disk searching for "This is a test". You will get much of the original file back quite intact.

If you are going to do this then do something that will write to every disk block.

This would be one approach:
dd if=/dev/urandom bs=64k of=/dev/rdsk/cXtYdZ

You could also use /dev/zero as an input device and multiple passes would be better still.

[Raj D.]

Hi Jay ,

I am with Clay , dd is most powerful and will do the trick , with /dev/zero , to wipe out the disk, .

hth,
Raj.

[rick jones]

Indeed, one wants to have multiple passes with different patterns.

However, I have heard that will not affect "spared" sectors.

The only _real_ way to _destroy_ all the data on a disc is to melt it into slag. Next to that, you could open the thing up and take a grinder to the platters and grind-away _all_ the oxide I suppose.