When you said incremental restore I thought you meant of the other volume groups, but on second reading I wonder if you mean incremental restore of rootvg.

What I have heard of as a solution is to use regular mysysb images (i.e. complete rather than incremental) of rootvtg to the nim server - and the nim server is also a client of TSM - to aid with the management of the individual mksysb's rather than a single 'clone' image that is a initial starting point for all systems.

The is nothing magical about booting using tftp. The magic of NIM is that is a system for managing installable images. AFAIK it is not an original IBM product, but something that IBM licenses, and has perhaps modified to make it suitable for both AIX and Linux installations and updates.

I have practically no knowledge of Tivoli products, solutions, or system management architecture. But from students what I hear that seems to be the most practicle solution is to have the NIM server be a TSM client - storing the rootvg mksysb images. What this also requires is that applications (data) are not part of rootvg. Then the changes to rootvg are relatively few.