Transcript Redundant Arrays of Inexpensive Disks

An Overview of
RAID
Chris Erickson
Graduate Student
Department of Electrical and Computer Engineering
Auburn University, Auburn, AL 36849
[email protected]
Objectives
Raid definition
Why RAID technology was invented
RAID structure
Current RAID applications
What is RAID?
Redundant
Array
Inexpensive / Independent
Disks
How does is work?
Requires 2 or more hard drives
Requires either hardware or software
controller logic
Allows disk drive storage to increase
speed, reliability, or both at a minimal
overhead cost
Why RAID?
Industries and companies require massive
amounts of data to be securely stored.
Tape storage is still prevalent for long
term, archival storage but not effective for
random access.
Hard Disk Drives are perfect for random
access in the Giga, Tera, Petabyte range.
More RAID background
Hard Disk Drives have a mean-time-to-error
With the possibility of error, regardless of how
small, something had to be done.
Hard Disk Drives have a latency involved with
seeking.
For a PC the latency is almost negligible. When
thousands of people are trying to access the
same location, something had to be done
RAID 0
Striped
Delivers very high performance
Requires 2 or more disk drives
Data
RAID 1
Mirroring
Delivers the exact same data to 2 disks. Used
for max redundancy and reliability.
Data
RAID 5
Stripe & Parity
Provides the speed of striping and provides the
parity for redundancy
Data
RAID 10
Provides dual RAID 1 configurations with
RAID 0 mirroring
Delivers the exact same data to 2 disks. Used
for max redundancy and reliability.
RAID 0
RAID 1
RAID 1
RAID
The more drives the better the benefits
RAID 5 is most popular for home & small office
users. It provides the most inexpensive solution
to have speed and reasonable reliability
RAID 10 – Used by large corporations for
maximum redundancy and reasonable speed
Completed !!
Any Question? Comments?