RAID 5 question

[xistenz]

Hopefully someone here can help me.

Is it possible to add another HDD to a RAID 5 array?

What I mean by that is, lets say I have 3 160GB HDDs in a RAID 5 array. I want more drive space. I want to add another 160GB HDD. Can I just add it to the array and the array will start using it, or do I have to back everything up, destroy the 3 HDD array, make a new 4 HDD array, and reinstall everything?

 

[stoke]

I have not seen the controller that can do dynamic raid 5, but there probably is one somewhere that can redistribute the configuration, and then I doubt that you're using it.

The parity information is being stored at key locations that are based on the total capacity of the set, adding another drive changes the capacity, and the key locations of the parity data.

But, there is a controller that simply uses one drive to store the parity set on, and it can cater for 5 drives in total, meaning that you could add the 4th and then a 5th drive if you're using that configuration, but I doubt it.