BTRFS vs ZFS for raid1 SSD cache pool - the definitive answer please

[brainbone_]

I'm adding a new 2x2tb SSD cache pool to have some redundancy there.

 

I have the option between BTRFS and ZFS.  I hear there's stability issues with BTRFS.  If BTRFS isn't able to consistently survive power being cut while using consumer SSDs, then it really isn't a viable option.  Is this the case?  (Of course I use a UPS, but we all know can UPSs fail, often at the worst time.)

So, is ZFS better in the regard?  And if so, why is BTRFS even an option?

[JorgeB]

Btrfs usually has no problem surviving a power cut, since writes are atomic, it can have issues (same for zfs) if the devices have write barrier issues and lie when all writes are not really done, this can be a firmware issue with some devices or controllers, having said that, zfs is considered the more robust of the two, so having the choice I would go with zfs.

[itimpi]

12 hours ago, brainbone_ said:

And if so, why is BTRFS even an option?

BTRFS has been an option for a long time while ZFS has only been recently added and is still being worked on.   In addition there are advantages to BTRFS in terms of its ability to easily add new drives to an existing pool in any combination of numbers and sizes whereas ZFS is far more strict with regard to this.

[brainbone_]

Thank you.