An Investigation into Transport Protocols and Data Transport ...

A.1. Data Storage 261
with the choice of appropriate hardware with optimised kernel and hardware
settings the effect of this bottleneck can be significantly reduced.
A.1.1
Overview
RAID stands for ‘Redundant Array of Independent Disks’ and is a method of
distributing the storage and retrieval of data across many, usually identical
hard disks. Depending on the configuration of the RAID, one may achieve
increased performance in terms of data access time and transfer rates, or one
may seek protection against data loss in case of hard drive failure.
The latter is important to ensure constant and continual availability of
storage systems as restoration from backups will often involve taking down
the system. Data stored in data protected RAID systems can also be recovered
with minimal hassle.
RAID controller solutions can be hardware or software implemented and
can be configured for different storage needs. As such, the performance of
several types of hardware RAID controllers, mounted on high performance
end systems, and types of RAID configuration are investigated.
Originally developed by D. Patternson [PGK88] in 1988, a series of RAID
configurations were defined which manufacturers have adopted 1 . Some of the
current RAID standards are outlined below.
• RAID-0: Commonly referred to as striping. It implements a striped
disk array whereby the data is broken down into blocks which are written
to separate hard drives in parallel. This solution provides no data
redundancy and therefore has very little overhead. It therefore offers
1 RAID-0 was not part of the original specifications, but presented later in 1994 in
[CLG + 94].