In an S5500 storage system, seven 1 TB SATA disks form a RAID 5 group. Two 500 GB LUNs are configured on the RAID group. The displayed remaining capacity is about 600 GB but the available capacity is only 300 GB when another LUN is configured.
Delete the second 500 GB LUN and then create another 500 GB LUN. In this way, the remaining capacity is physically continuous and another 600 GB LUN can be configured.
The customer creates three LUNs (500 GB, 300 GB, and 500 GB) on the RAID group in sequence and then deletes the 300 GB LUN manually. The remaining capacity is 600 GB but the 300 GB capacity released by the deleted LUN is separated from the unoccupied 300 GB capacity by the second 500 GB LUN. Therefore, the separated capacity cannot be allocated to a new LUN.
The capacity of a newly created LUN must be physically continuous.