I'm already sorry, if this question has been asked before, but i couldn't find something which fits my case.
We're running a NW6.5SP7 Server which had been Upgrade ever since NW4.11
In th Moment we have the traditional sys and vol1 Volumes and an _admin volume which seems to exist since the upgrade to NW5.1

These Volumes exist on a HW-RAID which we are planning to exchange

We were hoping also to change from trditional to NSS volumes

Can please anybody help and tell me what the fastest and safest way is?
There are about 400GB of data to transfer, also we want to get rid of the compression.

Any help would be appreciated