User guide

D-14 Compaq Smart Array 431 Controller User Guide
Example: Assume you have a total of 4 drives and you want to expand this to 6
drives. With Array Configuration Utility running, simply install two matching
drives in the empty drive bays. At this point your array will resemble Figure
D-10, 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, “Array Configuration
Utilities.”
The Smart Array 431 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 6 drives instead of 4. The Array
Configuration Utility also detects the unused space on each drive (because
each drive contains 4/6ths 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, will be configured into a single array with more
total capacity than the original one. Now your array will resemble Figure
D-10.
It is not necessary for all logical drives in an array to be the same size or even
have the same fault-tolerant configuration. Each logical drive is treated as a
separate entity no matter how many physical drives it crosses. Each may be
configured as best suits your needs.
It is important to remember that all physical drives in an array should be the
same size (capacity). This is because each drive contains an equal portion of
one or more logical drives and the portion sizes can only total the size of the
smallest drive. While you are not prevented from expanding storage capacity
with larger drives, the extra space cannot be used.
During expansion of an array that initially has two or more logical drives, the
redistribution of data takes place one logical drive at a time. When the capacity
expansion has completed, any newly created logical drive will become
available. Under Windows NT and NetWare, the new logical drive can then be
appended to your existing logical volume.