Check the error massage first. What was the error message when you did the smitty and it only increased 100 GB instead of 200GB? If it complained about excess the max space or something like that, then you just need to change the MAX pv for ndbvg, and add 100GB more afterward. If you didn’t see any error message, and after smitty, the total FS size became 500GB instead of 600GB, then make sure you’ve filled in the right number in 512 –byte block.

Your ndbvg shouldn’t be striping since you only have /db/run, one lv, I think you should be able to increase it just simply through smitty. But do make sure that the ndbvg is not stripping.

There are some attributes of the vg that can be change without backing up anything, but pp size is not one of them.