You can add a larger disk, but the extra space will not be utilized until all disks are at least that size. When the init is complete, your data volume will begin to expand automatically. X-RAID supports replacing each of your disks with larger capacity disks while keeping your data intact, whether you have 2, 3, or 4 disks. Just reboot the ReadyNAS to start the volume expansion which occurs in the background. When the process completes, your data will remain intact, but your data volume capacity will have expanded to 3x of the smallest capacity disk in your ReadyNAS.
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