Parity check starting with unmountable drive, precleared disk has data on it

[sonofdbn]

I'm setting up a new server and precleared both the 16TB parity drive (as a stress test, I believe preclearing isn't necessary for a drive that's going to be added as parity) and an 8TB data drive, which I think had data on it before. So I thought both disks should essentially just be blank.

 

After adding them to the array (they're the only two drives), a parity sync started, but at the same time a message popped up for the 8TB data drive: "Unmountable: Unsupported partition layout". So I cancelled the parity check and formatted the data disk. Now it's online but it says that 55.8GB is being used.

 

This seems weird - seems odd that a parity check would start when the disk is purportedly unmountable, and how did I end up with 56GB of data being used? For now I've stopped the array. 

t2-diagnostics-20230613-1546.zip

[JorgeB]

26 minutes ago, sonofdbn said:

Now it's online but it says that 55.8GB is being used.

This is normal for xfs, filesystem overhead.

 

27 minutes ago, sonofdbn said:

This seems weird - seems odd that a parity check would start when the disk is purportedly unmountable

Parity doesn't care about filesystems, and it still needs to sync.

 

 

[sonofdbn]

46 minutes ago, JorgeB said:

This is normal for xfs, filesystem overhead.

 

I must have added at least seven 8TB drives in unRAID and never noticed this really quite large overheard before.

 

47 minutes ago, JorgeB said:

Parity doesn't care about filesystems, and it still needs to sync.

 

My surprise was more that the message says "unmountable", but the disk must have been mounted for parity to be running.

[itimpi]

22 minutes ago, sonofdbn said:

but the disk must have been mounted for parity to be running

It is not a requirement that a disk be mounted for a parity check/sync to run - just that it is part of the array and not disabled.