NEC Express5800 User Manual page 97

RAID Levels
This section describes RAID levels that the Onboard RAID Controller (LSI Embedded MegaRAID)
supports. The available RAID levels are RAID0, RAID1, and RAID10 (striping of RAID1).
Characteristics of RAID Levels
The table below lists the characteristics of the RAID levels.
Level Function
RAID0 Striping
RAID1 Mirroring
RAID10 Striping of RAID1
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:
defected, the data saved in the HDD cannot be recovered.
Redundancy
No
Yes
Yes
RAID0 cannot have data redundancy. If a HDD is
RAID Controller
HDD 1
Stripe 1
Stripe 4
Configuring Your Server 4-37
Characteristics
Data read/write at the highest rate
•
Largest capacity
•
Capacity: (capacity of single HDD) ×
•
(number of HDDs)
Two HDDs required
•
Capacity: capacity of single HDD
•
Four or more HDDs required
•
Capacity: (capacity of single HDD) ×
•
((number of HDDs) / 2)
HDD 2
Stripe 2
Stripe 5
HDD 3
Stripe 3
Stripe 6