Chapter 7: Technology Background
RAID 5 – Block Striping with Distributed Parity
RAID 5 is similar to RAID 3 as described above except that the parity data is distributed across the disk drives along with the data blocks. In each case, the parity data is stored on a different disk than its corresponding data block.
RAID 5 makes efficient use of hard drives and is the most versatile RAID Level. It works well for file, database, application and web servers.
Distributed Parity
Data
Blocks
Disk Drives
Figure 4. RAID 5 Stripes all drives with data and parity information
The capacity of a RAID 5 disk array is the smallest disk drive size multiplied by the number of disk drives, less one. Hence, a RAID 5 disk array with four 100 GB disk drives will have a capacity of 300 GB. A disk array with two 120 GB disk drives and one 100 GB disk drive will have a capacity of 200 GB.
RAID 5 disk arrays on VTrak consist of 3 to 15 disk drives.
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