User manual

Appendix A: RAID

The capacity of a RAID 5 array is the smallest drive size multiplied by

the number of drives, less one. Hence, a RAID 5 array with four 100 GB

hard drives will have a capacity of 300 GB. An array with two 120 GB

hard drives and one 100 GB hard drive will have a capacity of 200 GB.

RAID 30 - Striping of Dedicated Parity Arrays

RAID 30 combines both RAID 3 and RAID 0 features. Data is striped across

disks as in RAID 0, and it uses dedicated parity as in RAID 3. RAID 30 provides

data reliability, good overall performance and supports larger volume sizes. RAID

30 also provides high reliability because data is still available even if two physical

disk drives fail (one in each array). RAID 30 requires a minimum of six disk

drives.

Data Drives Parity Drives

1 parity

3 parity

5 parity

2 parity

4 parity

6 parity

Data

Stripe

Figure 110. RAID 30 Striping of Dedicated Parity Arrays

RAID 50 - Striping of Distributed Parity Arrays

RAID 50 combines both RAID 5 and RAID 0 features. Data is striped across

disks as in RAID 0, and it uses distributed parity as in RAID 5. RAID 50 provides

data reliability, good overall performance and supports larger volume sizes. RAID

50 also provides high reliability because data is still available even if two physical

disk drives fail (one in each array). RAID 50 requires a minimum of six disk

drives.