I Disk Storage Technology
I.1
Most used RAID modes
RAID
(Redundant Array of Independent Disks) is a technology that is used to
increase the performance and/or reliability of data storage. A RAID system
consists of two or more disks working as a single logical unit for the purposes
of data redundancy or performance improvement. These disks can be solid
state or hard disks. There are different RAID levels, each optimized for a
specific situation. Some companies come up with their own unique
implementations.
HINT/TIP
Sometimes disks in a RAID system are defined as JBOD, which stands for “Just
a Bunch Of Disks”. This means that those disks do not use a specific RAID level
and act as stand
-
alone disks. This is often done for drives that contain swap
files or temporary data.
WARNING
RAID is no substitute for back
-
up!
All RAID levels offer protection from a single drive failure, except RAID 0.
For complete security, back
-
up of the data from a RAID system is always
required.
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The back
-
up will come in handy if two or more drives fail simultaneously
because of a power spike.
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It is a safeguard if the storage system is lost/fails all together.
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Back
-
ups can be kept off
-
site at a different location in case of a natural
disaster or fire destroying your workplace.
The most popular RAID levels are:
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RAID 0 – Striping (see "RAID 0 – Striping" on page 930)
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RAID 1 – Mirroring (see "RAID 1 – Mirroring" on page 931)
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RAID 5 – Striping with distributed parity check (see "RAID 5 – Striping with
parity" on page 932)
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RAID 10 – Combining RAID 0 & RAID 1 (see "RAID level 10 – Combining
RAID 0 & RAID 1" on page 933)
GEN3t
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I3995-3.1 en HBM: public