Cache Pool 50% utilization right away

[g33kf3r]

Hello everyone,
I have been using unraid for about 5 months now and I decided to upgrade from a single SSD to 3 m.2 drives to my unraid. 
AGAMMIXS70B-2T-CS1 - 2 TB (nvme0n1)

2INTEL_SSDPEKNU010TZ - 1 TB (nvme1n1)

2INTEL_SSDPEKNU010TB - 1 TB (nvme2n1)

 

After I moved everything from my cache to the array which it was about 100Gb from a 1TB SSD. 
I added those m.2 drives without any issues. 
I assigned the drives to the new cache pool and to my surprice is that out of the 3 drives which total 4TBs - I see that only 1TB is Free with 3.82MB used right away and It says 50% utilization already - mind you I have not even move anything from the arrays to the cache pool. Double check on the cache folder and nothing is there. 

Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme0n1p1  1.9T  3.7M  955G   1% /mnt/cache

My questions are - Did i do something wrong while setting up that cache pool? 
What can I do to fix this? 

Thank you

[trurl]

Default for multidisk pool is raid1 mirror so 2TB capacity is correct 

[JorgeB]

Free space will be wrong with an odd number of devices and raid1, it's a btrfs issue, used space will be correct and free space will get closer to real as the pool gets filled up.

 

[g33kf3r]

Thank you for the replies.