I apologize in advance if this has been covered, but I have not found an answer to a question I have in my brief search. Hopefully it will be an easy question to answer.

 

I am currently preparing for the process of changing my cache drive format from reiserfs to btrfs. I currently have a reiserfs formatted cache drive with my app data and docker image on it and would like to migrate the data to a new btrfs formatted ssd cache drive. In my search of the forums it appears that the most common sense method of doing this would be to copy my cache drive data to the array and then reassign the ssd as the new cache drive and then copy the cache drive data back to the new cache drive.

 

My question is whether I can save a copy step by simply reassigning my old cache drive as a new disk in the array and retain the data on it. Then I would be able to add the new ssd as a cache drive and copy the the data directly to it.

 

Hope this makes sense.  Thanks in advance.

You would lose parity protection until you rebuilt parity. Adding a drive to a parity protected array means you either have to clear the new drive first or set a new config that invalidates parity to allow the new drive to be added intact.

 

So... if you currently have valid parity, it will be much more work and riskier to add the drive to the array vs just copying the contents to a current array drive.

Thanks for the quick reply.  Makes perfect sense. I would ultimately have to rebuild parity in the above scenario (no time saved  ).

 

I guess I have another question then. Would it be possible to use the Unassigned Devices Plugin for this purpose? I have never used this plugin before.

 

Thanks again!

Unassigned devices plugin isn't verified for use with 6.1 yet.

It just so happens that I have not upgraded to 6.1 yet. Would you see any downsides to trying this out? or (another way to put it) IF Unassigned Devices plugin were verified for 6.1, would this be a way to use the plugin?

Should work.