Intel Application Accelerator, User Manual

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RAID 1 (Mirroring)
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4 RAID 1 (Mirroring)
A RAID 1 array contains two hard drives where the data between the two is mirrored in real time.
Since all of the data is duplicated, the operating system treats the usable space of a RAID 1 array
as the maximum size of one hard drive in the array. For example, two 40 GB hard drives in a RAID
1 array will appear as a single 40 GB hard drive to the operating system.
The primary benefit of RAID 1 mirroring is that it provides good data reliability in the case of a
single disk failure. When one disk drive fails, all data is immediately available on the other without
any impact to the data integrity. In the case of a disk failure, the computer system will remain fully
operational to ensure maximum productivity.
The performance of a RAID 1 array is greater than that of a single drive since data can be read
from multiple disks simultaneously, although disk writes do not realize the same benefit as is the
case with RAID 0.
Figure 2. RAID 1
Minimum Disks:
2
Advantage:
100% redundancy of data. One disk may fail, but data will continue to be accessible. A
rebuild to a new disk is recommended to maintain data redundancy.
Redundancy:
Excellent – disk mirroring means that all data on one disk is duplicated on another disk.
Application:
Typically used for smaller systems where capacity of one disk is sufficient and for any
application(s) requiring very high availability.
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