Smart Array Controller Technology: Drive Array Expansion and Extension
2
abstract
This paper describes four specific functions of the Smart Array Controller family:
capacity expansion; volume extension; RAID level migration; and stripe size
migration. Capacity Expansion adds physical drives to an array. This is usually
done in anticipation of additional changes to the storage configuration, such
as volume extension. Volume extension takes this newly available space in the
array and allows the OS to use it by increasing the size of an existing volume. If
administrators plan to perform volume extension on a Windows 2000 server,
they must be aware of specific requirements that must be met to perform the
volume extension. Administrators can also optimize their storage by using the
Array Configuration Utility to change either stripe sizes or RAID levels within an
array.
introduction
As data storage requirements increase and as computing needs change,
customers require flexibility not only within server configurations but also in
storage configurations. The Smart Array Controller family includes a standard
toolset that can be used to configure array controllers, expand an existing
array configuration by adding disk drives, or reconfigure an array by extending
volume sizes.
Customers find the abilities of online capacity expansion and volume
extension extremely worthwhile. However, these functions are not needed on
a daily basis; nor is it easy to remember the differences between the two
terms. As a result, customers sometimes find it difficult to distinguish between
the two. This paper presents a brief explanation of capacity expansion and
volume extension. The paper also briefly discusses other changes that an
administrator might want to make, such as RAID level migration and stripe size
migration.
This paper assumes that the reader is familiar with basic array controller
technology and terms. For those unfamiliar with drive array terms, a glossary is
included for reference.
array
configuration
utility
The array configuration utility (ACU)
1
is a local, graphical-based application
that helps configure Smart Array Controllers. As of this writing, the ACU is a
Windows–only utility capable of online configuration changes, that is, changes
while the operating system (OS) is running.
The array configuration utility XE (ACU-XE)
2
is a browser-based version of the
same utility. It is available to run online in Linux or Windows. Because ACU-XE is
a bootable CD, an administrator using other operating systems
3
can run the
utility offline by booting the system from the ACU-XE CD.
Customers using NetWare can perform capacity expansion and other
configuration changes through the NetWare Online Array Configuration Utility
(CPQONLIN), the online tool for array configuration.
1
For more information about ACU, refer to
http://www.compaq.com/products/storageworks/software-management/acu_matrix.html
2
For more information about ACU-XE, refer to
http://www.compaq.com/products/servers/proliantstorage/software-
management/acu_matrix.html
3
Customers should check the user documentation to verify that their specific array controller supports their chosen OS.
