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RAID 0 logical drives on ASUS DS300f G2 consist of one or more physical drives.
Advantages
• Implements a striped disk array, the
data is broken down into blocks and
each block is written to a separate disk
drive
• I/O performance is greatly improved
by spreading the I/O load across many
channels and drives
• No parity calculation overhead is
involved
Recommended Applications for RAID 0:
• Image Editing
• Pre-Press Applications
• Any application requiring high bandwidth
rAid 1 – M
irror
When a logical drive is mirrored, identical data is written to a pair of physical drives, while reads are performed
in parallel. The reads are performed using elevator seek and load balancing techniques where the workload
is distributed in the most efficient manner. Whichever drive is not busy and is positioned closer to the data is
accessed first.
With RAID 1, if one physical drive fails or has errors, the other mirrored physical drive continues to function.
Moreover, if a spare physical drive is present, the spare drive is used as the replacement drive and data begins
to mirrored to it from the remaining good drive
The logical drive's data capacity equals the smaller physical drive. For example, a 100 GB physical drive and a
120 GB physical drive have a combined capacity of 100 GB in a mirrored logical drive.
If physical drives of different capacities are used, there is unused capacity on the larger drive.
RAID 1 logical drives on ASUS DS300f G2 consist of two physical drives.
If you want a mirrored logical drive with more than two physical drives, see "RAID 1E – Enhanced Mirror".
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Disadvantages
• Not a true RAID because it is not fault-tolerant
• The failure of just one drive results in all data in an
disk array being lost
• Should not be used in mission critical
environments
Advantages
• Simplest RAID storage subsystem design
• Can increase read performance by
processing data requests in parallel since
the same data resides on two different
drives
Recommended Applications for RAID 1:
• Accounting
• Payroll
• Financial
• Any application requiring very high availability
rAid 1e – e
M
nhAnced
irror
RAID 1E offers the security of mirrored data provided by RAID 1 plus the added capacity of more than two
physical drives. It also offers overall increased read/write performance plus the flexibility of using an odd number
of physical drives. With RAID 1E, each data stripe is mirrored onto two physical drives. If one drive fails or has
errors, the other drives continue to function, providing fault tolerance.The advantage of RAID 1E is the ability to
use an odd number of physical drives, unlike RAID 1 and RAID 10. You can also create a RAID 1E Logical Drive
with an even number of physical drives. However, with an even number of drives, you obtain somewhat greater
security with comparable performance using RAID 10.
RAID 1E logical drives consist of three or more physical drives. You can create an array with just two physical
drives and specify RAID 1E. But the resulting array is actually a RAID 1.
Advantages
• Implemented as a mirrored disk array
whose segments are RAID 0 disk
arrays
• High I/O rates are achieved thanks to
multiple stripe segments
• Can use an odd number of disks
Recommended Applications for RAID 1E:
DS300f G2 Series User Manual
Disadvantages
• Very high disk overhead – uses only 50%
of total capacity
Disadvantages
• Very high disk overhead – uses only
50% of total capacity
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