Hey all,

 

If you setup a cache drive and setup your docker containers there for permanency, what happens when you add a second cache drive later? Does the cache pool need to be formatted in order to use the new space or will it magic add and balance the btrfs raid 1 mirroring?

 

Thanks,

Tom

If all works well you just need to add the disk to the pool and start the array, this will initiate a balance.

If all works well you just need to add the disk to the pool and start the array, this will initiate a balance.

 

This assumes your original Cache Drive is formated as BTRFS. If it's not BTRFS you can't cache pool, and you would have to format your cache first to BTRFS (wiping the data) before you actually can pool.

 

But yes if you have a BTRFS cache drive add the disk to the cache pool and it will balance the data.

Good point, maybe there should be a warning or something that btrfs is required when a user trys to use more than 1 cache slot, e.g, unsuspecting user has a XFS cache drive, changes cache slots to 2, adds a second disk do pool, starts array and cache will appear as unmountable.

Good point, maybe there should be a warning or something that btrfs is required when a user trys to use more than 1 cache slot, e.g, unsuspecting user has a XFS cache drive, changes cache slots to 2, adds a second disk do pool, starts array and cache will appear as unmountable.

 

Let's say I did this, how to undo it? if at all possible?

Good point, maybe there should be a warning or something that btrfs is required when a user trys to use more than 1 cache slot, e.g, unsuspecting user has a XFS cache drive, changes cache slots to 2, adds a second disk do pool, starts array and cache will appear as unmountable.

 

Let's say I did this, how to undo it? if at all possible?

 

If you didn't format the pool you can go back:

 

-unassign 2nd cache disk

-set cache slots to 1

-check that cache filesystem is set to xfs or auto

-start array and your cache disk will be back