Answer 1 by -Thomas Rush - From Quora
Will expanding a RAID 5 array wipe existing data? It *shouldn’t*. But that doesn’t mean that it *can’t*.
Best practice is to:
- Make sure your vendor even supports an on-line, non-destructive array expansion. I imagine most everybody does these days, but it’s not for certain. Read The Fine Manual.
- There’s always the chance for things to go wrong — from a sudden bad sector on a disk to a power failure. So… back up your data. Even if you only get an online backup service for a few months, it will be worth it if something does happen during the expansion. Of course, you should always have a backup of important data
Answer 2 by Pedro Lorentz-Myself-
As said the best medicin always backup your data because things will go wrong..Also you need to use the right HDD with same capacity, it should not cause any problems however nothing is garanteed…
I always recommend to anyone if you want to do something whatever it may be and if your data is important always backedup …thats is your anwser