Adaptec 6805Q 2270700-R Manuale Utente

Appendix B: Understanding RAID

●

101

RAID 50 Arrays

A RAID 50 array is built from six to forty-eight disk drives configured as two or more RAID 5 
arrays, and stripes stored data and parity data across all disk drives in both RAID 5 arrays. (For 
more information, see 

.)

The parity data provides data protection, and striping improves performance. RAID 50 arrays 
also provide high data transfer speeds.

Drive segment size is limited to the size of the smallest disk drive in the array. For example, 
three 250 GB disk drives and three 400 GB disk drives comprise two equal-sized RAID 5 arrays 
with 500 GB of stored data and 250 GB of parity data. The RAID 50 array can therefore contain 
1000 GB (2 x 500 GB) of stored data and 500 GB of parity data.

In this figure, P represents the distributed parity data.

RAID 5

B

RAID 50 

Logical Drive

=

1000 GB 

plus Parity

RAID 5

A

Each RAID 5 Logical Drive has 

500 GB Data Storage

250 GB Parity Data

Drive 1

250 GB

Drive 2

250 GB

Drive 3

250 GB

Drive 4

400 GB

Drive 5

400 GB

Drive 6

400 GB

1, 5, P

3, P, 9

P, 7, 11

2, 6, P

4, P, 10

P, 8, 12

Total Unused 
Space = 150 GB