Convert Cache containing cache-only shares on SSD Pool from BTRFS to XFS

[b0m541]

A long time ago I thought BTRFS was a good idea and set up all new hardware drives using BTRFS.

Later I changed my mind and wanted to convert everything to XFS. Over time I converted all data drives back to XFS.

However, the cache is still using BTRFS and I would like to change that.

 

Situation:

- Cache contains several shares that are held on the cache Only for performance reasons

- Cache is implemented on a pool of 2 SSDs

 

Questions:

- Do I need to convert to XFS I first need to empty the cache pool and then reformat it to XFS?

- How do I empty the cache from share data? There are different kinds of shares:

  - Yes: is it right to just run the mover once to move this to the data drives?

  - Only: is it right to firstly change these shares from Only to Yes and after that run mover once?

- Is there anything special to consider when reformatting SSD pools?

- After reformatting to XFS, set the shares which were formerly Only to Prefer (from Yes)? Run Mover once to move the content of these shares back to the cache? Then set the shares back to Only (from Prefer)?

 

Is this procedure correct?

Is there somewhere in the official or the community documentation a procedure described for this adventure?

 

Edited November 12, 2021 by b0m541

[b0m541]

Nobody ever did this?

 

[JonathanM]

Have you watched this?

 

 

[b0m541]

OK having seen the video and read the Cache issues section in the forum FAQ on unRAID V6 (https://forums.unraid.net/topic/46802-faq-for-unraid-v6/) I realize that my understanding of the RAID1 cache was limited/wrong.

 

What I actually wanted to have was XFS on top of 2 RAID1 SSDs, but now it seems to me that this is not possible using the UI.

Is it correct that the RAID1 setup of the cache is a feature of BTRFS and cannot be done (on UI level) with XFS?

 

 

[JonathanM]

28 minutes ago, b0m541 said:

 

Is it correct that the RAID1 setup of the cache is a feature of BTRFS and cannot be done (on UI level) with XFS?

Yes. XFS on pools is single drive only.

 

Theoretically there may be other options in the future, but for now the options are single disk XFS or software defined BTRFS RAID levels.

[b0m541]

Thanks for the clarification!