Removal of a disk - marked as missing?

[AmishJoe]

Hi All

 

I'll try to summarize a long story short:

 

I had an SSD cache. I ran into issues where it would fill up, and rather than data copy to then go straight to the array, it would just fail. So I removed the cache, and everything was happy. Remaining 12TB copied no problem.

 

Now, I want to re-add the SSD cache. To "start over" I decide to format the disk. To do so, I add it to the array, format it, then remove it from the array. Now, when I add it back as a cache, the array shows that it's missing the disk.

 

How can I convince the array that it doesn't need this disk anymore?

 

Thanks.

[trurl]

A formatted disk is an empty filesystem, not at all the same thing as a clear disk, so parity is no longer valid since you have removed one of the disks included in parity.

 

You will have to New Config, reassign your disks, and rebuild parity without that disk.

 

Be very sure you don't assign a data disk to the parity slot or it will be overwritten.

[AmishJoe]

I didn't have a clean parity in the first place.

 

So, New Config, reassign disks, will all the data be lost or will it be saved?

[AmishJoe]

Went ahead and did it, worst-case I had the data I could re-sync.

 

This seems to have done the trick, thanks! (But why is this so difficult? It seems like I should be able to remove a disk much easier than this...)

 

Thanks

[trurl]

Went ahead and did it, worst-case I had the data I could re-sync.

 

This seems to have done the trick, thanks! (But why is this so difficult? It seems like I should be able to remove a disk much easier than this...)

 

Thanks

Rebuilding parity is unavoidable* when removing a disk since the disk to be removed is included in parity.

 

 

*Actually there are more complicated ways of removing a disk without invalidating parity for command line gurus but most don't even bother.