Tried to find in docs but question on Pool drives.     Cache specific but probably any pool type.    So in my main UnRAID array I have several pools all have 2 like drives so they are  RAID1 mirrors essentially.   For cache support on another new UnRAID array I am building for a backup I put in 3 drives.   It looks ilke it mirrored 2 of the drives while the 3rd is a hot spare. 

 

Question is if I add a 4th like drive will this RAID 10 and basically mirror both and then stripe them together?     Or will it just make it another hot space?

 

I know UnRAID isnt a RAID just trying to reference the logic hope thats cool.    Thanks in advance all

Default is RAID1 for any number of drives added to the pool, unless you change that manually. Any valid BTRFS RAID level can be used, AFAIK.

 

See this link for how drives of various capacities will be used with the different RAID levels.

 

https://www.carfax.org.uk/btrfs-usage/

Thanks JonathanM I will toss a 4th drive in there and let it RAID 1 then.     Take care and Happy New Years!