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4-24 Configuring Your Server
RAID Levels
Characteristics of RAID Levels
The table below lists the characteristics of the RAID levels.
Level Function Redundancy Characteristics
RAID0 Striping No
•
Data read/write at the highest rate
•
Largest capacity
•
Capacity: (capacity of single HDD) ×
(number of HDDs)
RAID1 Mirroring Yes
•
Two HDDs required
•
Capacity: capacity of single HDD
Striping of both data
and redundant data Yes RAID5
•
Three or more HDDs required
•
Capacity: (capacity of single HDD) ×
((number of HDDs) - 1)
Striping of both data
and redundant data Yes RAID6
•
Three or more HDDs required
•
Capacity: (capacity of single HDD) ×
((number of HDDs) - 2)
IMPORTANT: To use RAID 5 or RAID 6, you need to additionally install the optional RAID
Upgrade Kit.
RAID0
In RAID0, data to be recorded is distributed to HDDs. The mode is called "striping".
In the figure below, data is recorded in stripe 1 (disk 1), stripe 2 (disk 2), and stripe 3 (disk 3)… in the order. Because RAID0
allows all HDDs to be accessed collectively, it can provide the best disk access performance.
IMPORTANT: RAID0 cannot have data redundancy. If a HDD is defected, the data saved in the
HDD cannot be recovered.
RAID Controller
HDD 1 HDD 2
Stripe 1
HDD 3
Stripe 4
Stripe 2
Stripe 5
Stripe 3
Stripe 6
RAID1
In the RAID1 level, data saved in a HDD is written to another HDD without change. The mode is called "mirroring".
When data is written onto a single HDD, the same data is written onto another HDD. If either of the HDDs is defected, the
other HDD containing the same data can substitute for the defected HDD. Thus the system can continue to operate without
interruption.