HP Compaq Integrated Smart Array Controller - Manual (Page 120)

B-14 Compaq Integrated Smart Array Controller User Guide
Compaq Confidential – Need to Know Required
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Part Number: 153236-001 File Name: i-appb Understanding Drive Arrays.doc Last Saved On: 8/27/99 11:35 AM
When initiated by the Array Configuration Utility, the Integrated
Smart Array Controller automatically redistributes the data in the original
logical drive to a logical drive that spans all of the physical drives in the array,
including the added drives. The room left over is used to increase the size of a
logical drive or create additional logical drives, also spanning all physical
drives. The extended logical drive is within the larger drive array. When
logical drives are added, both logical drives are then included in the drive
array with expanded storage capacity, as shown in the following figure.
Original
Logical
Drive
Added
Physical
Drives
Data from original logical drive redistributed over "Top" of all
physical drives.
New logical drive created over "Bottom" of all physical drives
or added capacity of the original logical drive.
Figure B-10. Expanded array storage capacity with a second logical drive
Example: Assume that you have a total of 14 drives and you want to expand
this to 18 drives. With Array Configuration Utility running, simply install four
matching drives in the empty drive bays. At this point your array resembles
Figure B-9, with the original data (original logical drive) represented by the
gray shaded drives and the new drives unshaded. Run the Array Configuration
Utility, which is located on the Compaq SmartStart and Support Software CD,
to start the expansion process described in Chapter 6.
The Integrated Smart Array Controller redistributes the data to an equal
portion of all the drives, using the same fault-tolerance method as the original
configuration. The first logical drive remains first, but it now spans 18 drives
instead of 14. The Array Configuration Utility also detects the unused space
on each drive (because each drive contains 14/18ths of the data that it used to)
and helps you configure it into a second logical drive with its own fault
tolerance, distributed over the extra space of all the drives.
When this process is finished both logical drives, one containing the original
data and the new empty one, are configured into a single array with total
capacity than the original one. Now your array will resemble Figure B-10,
using the same shading scheme to represent the logical drives.