Drive arrays, Logical drives – HP Compaq Integrated Smart Array Controller User Manual
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B-4 Compaq Integrated Smart Array Controller User Guide
Compaq Confidential – Need to Know Required
Writer: CDresden Project: Compaq Integrated Smart Array Controller User Guide Comments:
Part Number: 153236-001 File Name: i-appb Understanding Drive Arrays.doc Last Saved On: 8/27/99 11:35 AM
Drive Arrays
Drive arrays on the Integrated Smart Array Controller have several important
attributes:
■
A single array cannot span more than one Integrated Smart Array
Controller.
■
A single Integrated Smart Array Controller can control multiple arrays.
■
Arrays must have at least one and may have up to 15 physical drives.
■
Arrays consist of at least one and may have up to 32 logical drives with
a maximum of 32 logical drives per controller.
■
For maximum space efficiency, all drives in a single array should be of
the same capacity.
Logical Drives
The concept of logical drives is an important one. A logical drive is storage
space that is distributed across all physical drives in an array (except for online
spares). Distributing storage space provides efficiency and security:
■
Data can be accessed on all physical drives at once, resulting in much
higher performance data storage and retrieval.
■
Fault-tolerance methods can be used to protect your data against
hardware failures.
An array can consist of several logical drives, each spanning all of the physical
drives in the array. It is important to note that the part of any one logical drive
residing on each physical drive is the same size. This means that for maximum
space efficiency, all physical drives in each array should also be the same size.
Logical drives have these important attributes:
■
There must be at least one and up to 32 logical drives in an array
(maximum 32 logical drives per controller).
■
Logical drives in an array may have different individual storage
capacities.
■
Logical drives in an array may use different fault-tolerance or RAID
methods.
■
The portion of a logical drive on each physical drive is the same size.