Last time I checked, VNXe require specific drive counts for RAID types and disks are sold in packs to facilitate this.  SAS disk are configurable in RAID5 in 6+1 config (1 parity) and only expandable similarly. You'd need to have 7 disks available to expand your current pool, so you'd end up with a pool comprising of 2 x (6+1) disk groups.  (SAS are also configurable in RAID 10 with a 3+3 config). I've never particularly liked this requirement but for the great $ there are compromises.  You may be able to buy drives singularly to make the required number.
Hello All How to add the odd number of disks to the VNXe3300 as I have few disks left on the DPE, which is not letting me add. Current Config - RAID5 - Disks added 7 Remaning disks on the DAE - 4 HS - 1 I would like to add remaining disks to the pool. Its saying insuffcient disks . Is there any way to add the disks through CLI.  Regards AUP_it
How to add odd number of disks VNXe3300