Why scrub a new array?

[thany]

I've just set up a brand new server with a brand new installation of unRAID, latest stable version. I've set up the main array - 5 8TB disks, totalling 32TB with one parity disk.

 

Immediately after creating the array the parity disk goes into "invalid" state. While maybe technically correct, it is not a great first impression for novice users of unRAID, but I understand where this is coming from. Parity has not been scrubbed yet, so it becomes healthy once that's done.

 

But here's the thing, right: why scrub a NEW array at all? Surely scrubbing can be skipped for empty drives, and be put into a healthy state. Kind of like the different between quick format and full format in any desktop OS. The problem with this is that it will take a super long time before a newly created array is in a state where it's considered safe by unRAID, and then scrubbing isn't affecting performance anymore as well.

 

Concretely my question is: can I make it skip scrubbing for parity and throw it into a healthy state right away? Again, the drives are empty. There should be nothing to scrub, iyam.

Edited October 7, 2022 by thany

[JorgeB]

22 minutes ago, thany said:

Surely scrubbing can be skipped for empty drives

It cannot, drives can be empty but not be all zeros dues to previous data, only new never used drives would really be empty.

[thany]

Ah okay, so it also involves zeroing the data if I understand correctly?

[JorgeB]

It involves syncing the existing disks with parity, if the disks have been used before they won't be all zeros so parity needs to be updated accordingly, and even on new disks there are no guarantees they are all zeros, though they usually are, Unraid need to make sure, or there could be data loss later.