I did some searching but couldn't seem to find a solution to my particular problem.  Over black friday I picked up an M2 2TB ADATA SSD to replace my old 240GB SATA cache drive.  I popped the NVMe drive in, moved the data off of my old cache drive, stopped the array, and tried to start it back up with the M2 drive as the cache drive, but I'm getting this error about "unsupported partition layout".  Even when the array is stopped and the new drive is unassigned, there is a "FORMAT" button next to it, but the button is greyed out and doesn't do anything when I click it.  

 

I checked my log and I'm getting a weird looping error with unassigned devices plugin and the ca.backup plugin, but I'm not sure if those are related (log attached). 

 

Thanks for any help.  

 

 

log.txt

EDIT: Don't be like me.  Never preclear an SSD.  

 

So I've solved this problem and reporting back in case anyone else finds this thread for the same issue I had.  

 

First off, I fixed the drive issue by running pre-clear on the disk.  I had heard that you don't need to preclear SSDs (and it tends to make them overheat), but oh well, it worked.  

 

And for the other random errors, those were from having old GUI windows open that had been left open prior to the restart of the system.  

Edited December 7, 20196 yr by pzycho
Updated Info

4 hours ago, pzycho said:

So I've solved this problem and reporting back in case anyone else finds this thread for the same issue I had.  

 

First off, I fixed the drive issue by running pre-clear on the disk.  I had heard that you don't need to preclear SSDs (and it tends to make them overheat), but oh well, it worked.  

 

And for the other random errors, those were from having old GUI windows open that had been left open prior to the restart of the system.  

Your post need a major correction or people may end up nuking their SSD.

 

CORRECTION:

TL;DR - do NOT preclear SSD.

 

Preclearing SSD is not a "need not" but rather a "should not" and it has nothing to do with overheating the SSD.

 

Preclear has 2 main uses - stress test HDD on arrival before adding to the array (due to high early failure rate) and zero out the disk (so parity doesn't have to be recalculated).

• SSD has lower early failure rate than HDD (due to not having moving parts, think UPS driver dropping your HDD sorta early failure) hence, the need to stress test is reduced.
• As everyone knows by now, SSD cells have limited write cycles so unnecessary write should be avoided.

So based on the above, running preclear will just unnecessarily waste a whole write cycle for no reason really, especially since the SSD is not added to the array (with parity) but rather to the cache pool.

 

Now depending on the controller, pre-clear activities may confuse it and interfere with the wear-leveling and garbage collection algorithm.

• At best, everything works and you just waste a write cycle.
• At worst, it can cause WL and GC go crazy causing significant write amplification i.e. it MAY nuke your SSD.

So unless there's a very good reason to do it (which I can't see any right now), do NOT preclear SSD.

 

 

To the OP: 

There is instruction on how to replace drives from a btrfs cache pool, which I don't think you have followed (or not followed properly).

You can probably go have a celebratory beer now cuz what you did could have gone rather wrong.

Next time, please wait for advice.

Whoops. 

 

There once was a man on Unraid, 

An upgraded drive he did crave

He ran a preclear without any fear

and almost sent his new drive to its grave.

Edited December 7, 20196 yr by pzycho