DS8000 Disk Capacity
The effective capacity of the DS8880 is determined by the following factors:
▪The spare configuration
▪The capacity of the installed drives
▪The selected RAID configuration
▪The storage type:
– Fixed block (FB), including IBM i
– CKD (count-key data)
The DS8880 operates in a RAID 6, RAID 10, or RAID 5 configuration. The following RAID configurations are possible:
▪5+P+Q RAID 6 configuration: The array consists of five data drives and two parity drives. The remaining drive on the array site is used as a spare.
▪6+P+Q RAID 6 configuration: The array consists of six data drives and two parity drives.
▪3+3 RAID 10 configuration: The array consists of three data drives that are mirrored to three copy drives. Two drives on the array site are used as spares.
▪4+4 RAID 10 configuration: The array consists of four data drives that are mirrored to four copy drives.
▪6+P RAID 5 configuration: The array consists of six data drives and one parity drive. The remaining drive on the array site is used as a spare.
▪7+P RAID 5 configuration: The array consists of seven data drives and one parity drive.
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Note: RAID 6 is the recommended and default RAID type for all drives, and it is the only supported RAID type for 7.6 TB and 15.6 TB Tier 1 drives.
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See the IBM DS8880 Introduction and Planning Guide, GC27-8525 for the effective capacity of one rank in the various possible configurations: