Looks to the system like: One
C:\ Drive double the size of each disk (ie: two 100 gig
drives looks like a single 200 gig drive on the system)
RAID Level 0 is a performance
oriented striped data mapping technique.
Uniformly sized blocks of storage are assigned in
regular sequence to all of an array's disks.
Advantages: RAID 0 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.
What the heck does that mean?
Exactly, why does the industry have to be so complex
about every cotton pickin' thing? It simply means your
data is taken, split in half and one half of each chunk
of data is written to each disk at the same time.
Data is also read off the disks in the same manor. This
is where the speed comes from.
A real simple analogy to understand
this concept is if you wanted a deck built on your
house. Your friend who is a carpenter comes over and
says it will take 16 man hours to build this deck. The
actual time it takes to build your deck with 1 carpenter
working is 16 hours, or two 8 hour days. If your friend
brings another carpenter though, the time it takes to
build the deck stays constant at 16 hours, but the time
to complete the deck is now 1 day because each man is
doing 8 hours of work. Same thing with hard drives.
The reliability of RAID Level 0,
however is less than that of its member disks due to its
lack of redundancy. The failure of just one drive will
result in all data in an array being lost. Should never
be used in mission critical environments.
RAID1: "Mirroring".
Recommended Applications:
Accounting � Payroll � Financial � Any application
requiring very high availability.
Looks to the system like: One
C:\ Drive the size of each disk (ie: two 100 gig drives
looks like a single 100 gig drive on the system)
RAID Level 1, also called mirroring,
has been used longer than any other form of RAID. It
remains popular because of its simplicity and high level
of reliability and availability. Mirrored arrays consist
of two disks. Each disk in a mirrored array holds an
identical image of user data.
A RAID Level 1 array may
use parallel access for high transfer rate when reading.
More commonly, RAID Level 1 array members operate
independently and improve performance for read-intensive
applications. This is a good entry-level redundant
system.
Advantages: One Write or two Reads
possible per mirrored pair. Twice the Read transaction
rate of single disks. Same write transaction rate as
single disks. 100% redundancy of data means no rebuild
is necessary in case of a disk failure, just a copy to
the replacement disk. Transfer rate per block is equal
to that of a single disk.
What the heck does that mean?
Your data is duplicated and written to both
disks at the same time. A slight speed improvement over
a single drive in that each drive can be read
independently.
