Half of disk space missing on RAID1, all disks it seems to be ok

Half of disk space missing on RAID1, all disks it seems to be ok

Hi there. I have a problem with raid array. I miss it a half.
My disks layout is
2 x 250 gigabytes velociraptors (Array_0000)
2 x 1TB velociraptors (Array_0001)
....both connected in RAID1. OS is Windows Server 2012.
Array_0001 is formated in ReFS FileSystem. On Array_0001 is only SQL
Server databases. SQL takes about 50 gigabytes. http://d.pr/i/bCiw
Array_0001 has 1TB total capacity and this is problem. Showing only 480 gb
free. http://d.pr/i/R3do
I have to be shown the system files, On the disk they are not swap or
hibernate file. This is disk management .....(i have no rights to post
other links :( ) And this intel rapid storage manager .... (i have no
rights to post other links :( ) i need 10 reputation poits. I try add
images to comments. Anyone know this mystery?