Here is one you don't come across very often!

Setup by my predecessor:
Non-clustered (part of a DS tree) NW6.5 server with the following storage config:

3 x 146GB Raid 5 array - contains SYS, DATA NSS VOLUMES
4 X 146GB individual drives (no fault tolerance!)- each has been added to the pool and contains a segment of DATA volume.
Total data on all 5 logical (or 7 physical) drives - 700GB

Obviously this is very risky in that if one of the single drives fails, there goes DATA (and SYS?).
Plan is to build the 4 drives into the raid5 array subsystem.
I am having trouble understanding the implications of breaking and restoring it. If I were to erase and build the single drives into the existing raid5 array, this will destroy DATA, but will it affect SYS? Will SYS and the OS still be as it was and usable? Or does this affect the whole pool and all it's Volumes?

Then when I come to restore from tape, will this cause a problem with the POOL and hence the volumes because the physical drive subsystem has changed? - now there will be only one logical drive instead of five.
I might be over-thinking this too much and if SYS is intact, I just need to create a new pool and restore the DATA volume into it? But then, does this cause issues with volume mounting or security / user rights etc. now the POOL makeup has changed?
Would (Portlock) imaging the whole server off and back on, be a better option or will I face the same issues?

I can't help but think the only option is to migrate to another disk subsystem using volume move etc.
Any help and option suggestions very much appreciated!