Notes: Reserved capacity for system is the space allocated for the system partition and SWAP partition. These partitions are used for installing the operating system, storing system data and temporary data, etc. Each drive in the RAID must reserve approximately 10 GB of system space. Learn more Available capacity refers to the capacity that can be used to create volumes after the RAID is configured. When creating a volume, the system will reserve capacity for metadata. Volumes with Btrfs file system reserved 4% of the capacity for metadata, and 2% for volumes with ext4 file system. As a result, the actual available capacity for storing data in the volume will be less than the estimated available capacity provided by the RAID Calculator. Please refer to Synology Storage Manager to understand the actual available capacity of the volume. Synology RAID Calculator recommends models based on the total number and capacity of the selected drives. Some models may not support drives of certain capacities, but the total capacity can still be achieved through other combinations or by pairing with expansion units. Please refer to the Synology Products Compatibility List to see which drives are compatible with your Synology product. RAID types and the maximum capacity of a single volume supported may vary by model. Please refer to your Synology product's DataSheet to understand the software specifications supported by each model. If you plan to use drives of different capacities to compose a RAID, it is recommended to use SHR or SHR-2 to minimize the waste of unused space. Learn more