Hallo,
ich würde dieses IBM Dokument nehmen:

Document Title
Initialize Disk Drives So That All Data Is Erased Off of a System

Document Description
In some cases, a customer may wish to erase all data off their system. They may want to do
this because they are getting rid of it and do not want any of their data on it.

No Partitions:

The procedure for doing this follows:

1 Do a D Manual IPL using a SAVSYS, full system save, or LIC Install CD.
2 The first menu will give an Option 1 to Install LIC, and Option 2 to use DST. Select Option 1.
3 The Install LIC menu will provide 5 options. Select Option 2 to Install Licensed Internal Code and Initialize System.
4 After the install of LIC is complete, the system will IPL to the DST primary menu.
5 Configure all the disk drives by adding them into system ASP (ASP1).
This writes zeroes on the disk drives so only the LIC is loaded.
o Select Option 3 - Use DST.
o Work with Disk Units.
o Work with Disk Configuration.
o Work with ASP Configuration.
o Add units to ASPs.
o Type 1 in front of all the available units.
6 When that is complete, power off the system by pressing the power button two times.

System is clean and ready to go.

Partitioned System:
(This will remove all partitions and erase all data on drives from all earlier partitions.)

The procedure for doing this follows:

1 Do a D Manual IPL using a SAVSYS, full system save, or LIC Install CD of the primary partition.
2 The first menu will give an Option 1 to Install LIC, and Option 2 to use DST. Select Option 1.
3 The Install LIC menu will provide 5 options. Select Option 2 to Install Licensed Internal Code and Initialize System.
4 After the install of LIC is complete, the system will IPL to the DST primary menu.
5 Take the option to Work with system partitions.
6 Take the option to Recover configuartion data.
7 Take the option to Clear non-configured disk unit configuration data.
8 Exit back to the DST primary menu.
9 Configure all the disk drives by adding them into system ASP (ASP1).
This writes zeroes on the disk drives so only the LIC is loaded.
o Select Option 3 - Use DST.
o Work with Disk Units.
o Work with Disk Configuration.
o Work with ASP Configuration.
o Add units to ASPs.
o Type 1 in front of all the available units.
10 When that is complete, power off the system by pressing the power button two times.

System is clean and ready to go