Infortrend RAID Controller Manual

Chapter
2
1 2
3
Logical Drive
Functional Description
Redundant Arrays of Independent Disks, or RAID, offers the following
advantages: Availability, Capacity, and Performance. Choosing the
right RAID level and drive failure management can increase Capacity
and Performance, subsequently increasing Availability. Infortrend's
external RAID controllers provide complete RAID functionality and
enhanced drive failure management.
2.1 Logical Drive
Figure 2 - 1 Logical Drive
The advantages mentioned above are achieved by creating
“logical drives.” A logical drive is simply an array of
independent physical drives. The logical drive appears to the
host the same as a local hard disk drive does.
The following section describes the different methods by which
logical drives are created, such as spanning, mirroring and data
parity. These methods are referred to as “RAID levels.”
2.2 Logical Volume
What is a logical volume?
The concept of a logical volume is very similar to that of a logical
drive. A logical volume is composed of one or several logical drives.
The member logical drives can be composed of the same RAID level or
each of different RAID levels. The logical volume can be divided into
a maximum of 8 partitions. During operation, the host sees a nonpartitioned
logical volume or a partition of a partitioned logical
volume as one single physical drive.
Functional Description 2-1