creating a infinite retention policy time

You can create a very long policy for Decades etc.

But remember that every type of tape, sooner or later, will reach the end of its lifetime.

Hi,

You should think about archive system rather that backup. Of course you can do this with NW but I think that somethink like diskextender or a kind of HSM system will be much proper for you. Anyway set the long retention policy (10/20/30 years for a savesets).

Yes, -e forever argument for save will do that, but it doesn't make sense as others have pointed out. Also, depending on NW version (not sure about 7.1.4, but I guess that version too) you could be blocked by code due to date array used so your retention might restricted to year 2038 (32 bit limit) for which patch exists.