I installed my UnRaid server (unregistered), assigned and formatted the drives (2 2TB data drives and 1 2TB parity drive), ran a parity check, and started the array, all before I read anything about "pre-clearing" the drives before assigning them to the array. I'm very impressed by the product so far, and even though I still have a lot to learn, I've upgraded to the plus version. Post Unraid upgrade, I've upgraded my parity drive to 3TB, so now I have an extra 2TB (old parity drive) available to add to the array. My question is: Is it worth the effort to run the pre-clear script on a drive that's already been formatted and used as a parity drive? And a follow on to that question, should I go back and pre-clear the data drives I have installed in the array?

No need to pre-clear the drives you're already using -- they're being tested by simply being used.    Wouldn't hurt to do so, if you want the added "peace of mind" of thoroughly testing them ... but they're getting a full read test anytime you do a parity check.

 

As for the 2TB that was parity -- it's already been completely written during the initial parity sync, and fully read when you did a parity check.    Nevertheless, you may want to pre-clear it simply so it can be added very quickly, instead of rendering your server unuseable while it's being cleared.

 

Thanks Gary