Fujitsu Siemens Computers JMicron JMB362, User Manual

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Introduction
The JMicron JMB362 RAID Host Controller supports RAID levels RAID 0, RAID 1 and SPAN (JBOD).
The following table provides an overview of these RAID levels.
RAID level
Number of hard disk
drives
Capacity Bene fi ts
RAID 0 (striping) 2 Number of drives x
smallest size Highest performance,
no data protection
RAID 1 (mirroring)
2
Smallest size
Data protection
SPAN (JBOD) 2 Sum of all hard disks No performance
advantages, no data
protection
RAID 0 (striping)
Reads and writes data sectors across multiple hard disks using interleaving.
RAID 0 does not support fault tolerance. Any data loss will affect the entire
disk array if a single hard disk fails.
RAID 0 is designed to provide the highest performance. The data capacity of the disk
array is equal to the number of hard disks multiplied by the capacity of the smallest hard
disk. The block size can be set between 4 Kbyte and 128 Kbyte.
RAID 1 (mirroring)
Writing of identical data to both hard disks (redundancy, mirroring) and parallel reading.
If one of the mirrored hard disks fails or no longer reacts due to a mechanical fault, the remaining
hard disk will continue to operate individually. This protects against data being lost.
Due to this redundancy, the data capacity of the disk array is equivalent to
the capacity of the smallest hard disk.
SPAN (JBOD)
With a SPAN disk array, the data capacity is equivalent to the sum of all the hard disks used. These
can be of different sizes. The operating system treats the combined drives as a single drive.
"Spanning" means that data will be saved on one hard disk until it is full. Data will be
saved to the next hard disk in the disk array as soon as the
fi rst disk is full. The entire
disk array will be affected if a single hard disk fails. SPAN (JBOD) is not technically
categorised as RAID and does not support any error tolerance features.
2 - English 10600854936, edition 1