Promise Technology EX8650, EX8658, EX8654, EX4650 Choosing a RAID Level, Advantages Disadvantages

SuperTrak EX Series User Manual

Choosing a RAID Level

There are several issues to consider when choosing the RAID Level for your logical drive. The following discussion summarizes some advantages, disadvantages and applications for each choice.

RAID 0

Advantages	Disadvantages
Implements a striped logical drive, the	Not a true RAID because it is not fault-
data is broken down into blocks and	tolerant
each block is written to a separate	The failure of just one drive will result
physical drive
	in all data in an logical drive being lost
I/O performance is greatly improved by	Should not be used in mission critical
spreading the I/O load across many	environments
channels and drives
No parity calculation overhead is
involved

Recommended applications for RAID 0:

•Image Editing

•Pre-Press Applications

•Any application requiring high bandwidth

RAID 1

Advantages	Disadvantages
Simplest RAID storage subsystem	Very high physical drive overhead –
design	uses only 50% of total capacity
Can increase read performance by
processing data requests in parallel
since the same data resides on two
different drives

Recommended applications for RAID 1:

•Accounting/Financial

•Payroll

•Any application requiring very high availability

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