What is the best way to protect yourself when your cache disk dies? Assuming you are running a few dockers etc.

Well the usual methods are:

[*]Run a BTRFS cache pool in at least RAID-1 so the failure won't result in data loss.

[*]Make use of the ability of Community Applications to reinstall docker containers using the original template.  That will let you rebuild your docker image.

[*]Make use of Community Applications Backup/Restore to backup the appdata component of your dockers.

Are you feeling comfortable with those, or looking for more?

Those are great and appreciated.

 

So lets say RAID 1 scenario, are we talking hardware RAID then? We need a RAID controller in our system? If so, when the failure occurs, nothing is affected, we are still up and running, just need to replace the failed disk?

Or is this software BTRFS RAID 1?

 

The backup and restore is straightforward.

Software BTRFS RAID-1, built in functionality for unRAID 6+.  I'm not running it, but I understand that access should be seamless in the event of a failure.

 

Using a hardware RAID controller is another option.  Compatibility is an issue - the controller would need to present the hardware array as a single device that unRAID could mount as a disk.  Some controllers work, others don't.  Some folks use Areca controllers?

Ok good to know, may implement the software RAID 1 now that I have expansion room.

 

Thanks

One more question, can you add a second cache disk and implement BTRFS RAID 1 after already having a cache disk configured and in use? Or does it have to be done when you are setting up the cache disk from scratch?

If your existing single cache disk is BTRFS formatted then you can add another to make a pool. If it's XFS formatted you need to re-format it.

 

Pretty much all you need to know about using, changing, and maintaining cache pools is in the unRAID V6 FAQ sticky.

Ok so my existing cache disk is XFS, what do I do or how can I back it up so I can format it and copy everything back and add a second cache drive for RAID 1?

Ok so my existing cache disk is XFS, what do I do or how can I back it up so I can format it and copy everything back and add a second cache drive for RAID 1?

You can just follow the FAQ entry for replacing a single cache device except instead of replacing it you would just reformat it.