Drobo Gen 2 Speed 3 MB/s


I know speed been always a topic but thought of posting and asking nevertheless.
I am stuck on this low speed, thinking if it might be a hardware issue with the drobo.

connected via firewire on a mac.

checked with blackmagic speed test

all 4 bays are loaded with 2-4 TB disks

and quite often I have to use diskwarrior to rebuild otherwise it would not mount.