Promise Technology VTrack M-Class M200i - Manual (Page 251)

Chapter 7: Technology Background
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RAID 5 – Block and Parity Stripe
RAID 5 organizes block data and parity data across the physical drives.
Generally, RAID Level 5 tends to exhibit lower random write performance due to
the heavy workload of parity recalculation for each I/O. RAID 5 is generally
considered to be the most versatile RAID level
Figure 3. RAID 5 Stripes all drives with data and parity information
The capacity of a RAID 5 disk array is the smallest drive size multiplied by the
number of drives less one. Hence, a RAID 5 disk array with (4) 100 GB hard
drives will have a capacity of 300GB. A disk array with (8) 120GB hard drives and
(1) 100GB hard drive will have a capacity of 800GB.
RAID 5 arrays consist of three or more physical drives.
Recommended applications: File and Application Servers; WWW, E-mail, News
servers, Intranet Servers
Data
Blocks
Distributed Parity
Disk Drives