If you're going to expand an existing volume, please read Expand Volumes or Disk Groups by Adding Hard Disks and Expand Volumes or Disk Groups by Replacing Hard Disks for detailed information.

The result of calculation helps you evaluate the available space when you are creating a new volume only.On the contrary, Unused space under other RAID types indicates the space that can't be utilized and is thus wasted. When using SHR or SHR-2 HDD protection as your RAID type, the Unused space will be automatically reserved for future expansion.Please refer to the specifications of each model for detailed information.

RAID F1 and SHR are only available on selected models.Please refer to Synology Storage Manager for precise data calculations for storage installed on your Synology NAS. The actual HDD size will be affected by the system partition and can vary between vendors, so the values calculated may differ from the actual results. Synology RAID Calculator offers you an estimate on the space utilization with various mixed HDD configurations and RAID types.Visit here for more information on choosing the correct HDD for your Synology NAS.

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