Appendix B: Selecting the Best RAID Level ● 157RAID 10 Logical DrivesA RAID 10 logical drive is built from two or more equal-sized RAID 1 logical drives. Data in aRAID 10 logical drive is both striped and mirrored. Mirroring provides data protection, andstriping improves performance.Drive segment size is limited to the size of the smallest disk drive in the logical drive. Forinstance, a logical drive with two 250 GB disk drives and two 400 GB disk drives can create twomirrored drive segments of 250 GB, for a total of 500 GB for the logical drive, as shown in thisfigure.Disk Drive 1Disk Drive 2Disk Drive 3Disk Drive 4250 GB250 GB400 GB400 GBDrive Segment Size (Smallest Disk Drive)Disk Drive 2Disk Drive 3Disk Drive 4Disk Drive 11 3 ... 4992 4 ... 5001 3 ... 4992 4 ... 500Unused Space = 150 GBDisk Drives in Logical Drive RAID 10 Logical Drive = 500 GBUnused Space = 150 GB
