Are you planning to use them for NAS by the data movers ?  If yes then you need to keep in mind the support raid configs for NX4 and SATA they are  2+1 RAID5 3+1 RAID5 4+1 RAID5 5+1 RAID5 RAID 1/0 (2 disk) 4+2 RAID 6  None of these fit 8 disks - so I suggest you stick with what you have  Also just 1 LUN wouldn’t be not optimal – you want at least 2 – better 4  Once you have delete all your old file systems all space should be returned to the system pool and you can create large file system spanning both raidgroups if you like
I just purchased a VNXe and moved all my virtual servers over. All I have left is CIFS server and some left behind files. I would like to blow out all the SATA drives and create one large storage pool to run AppAssure backup on? I am having trouble figuring out how to get started. The current SATA drives have two virtual disk and one is being used by the CIFS server the other is blank. I am really green when it comes to the NX4 configuration and would appreciate any help. Thanks, Don   
NX4 reconfigure drives