hp industry standard servers technology brief table of contents october 2002 Smart Array Controller Technology: Drive Array Expansion and Extension abstract introduction array configuration utility capacity expansion logical drive creation volume extension volume extension in Windows RAID migration stripe size migration conclusion feedback glossary 2 2 2 3 4 5 6 7 8 8 9 9 1
Smart Array Controller Technology: Drive Array Expansion and Extension 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.
Smart Array Controller Technology: Drive Array Expansion and Extension capacity expansion Capacity expansion is the process of adding physical drives to an array that has already been configured. The logical drives (or volumes) that exist in the array before the expansion takes place are unchanged. Only the amount of free space in the array changes. For example, suppose that an existing array consisted of four physical drives and the administrator wants to expand the capacity to six physical drives.
Smart Array Controller Technology: Drive Array Expansion and Extension logical drive creation Once the drive capacity has been expanded, the added capacity can be used to create a new logical drive (figure 2) or to extend the size of an existing logical drive (as described in the section titled volume extension). Some people might want to add a new logical drive, for example, if every department in a company had its own logical storage volumes.
Smart Array Controller Technology: Drive Array Expansion and Extension volume extension Volume extension grows the storage space of a logical drive (see figure 3). During this process, an administrator adds new storage space to an existing logical drive on the same array, usually after the array has been expanded. An administrator may have gained this new storage space by either capacity expansion, as previously discussed, or by deleting another logical drive on the same array. figure 3.
Smart Array Controller Technology: Drive Array Expansion and Extension volume extension in Windows Operating systems within the Windows family support online drive extension under specific conditions. To understand these conditions, an administrator must first recognize the differences between Windows basic and dynamic disks. A basic disk uses Microsoft’s classic partition system in which each volume uses only one partition. This system is the default in Windows NT, Windows 9x, and DOS.
Smart Array Controller Technology: Drive Array Expansion and Extension RAID migration Administrators may perform volume extension in order to increase raw data storage capacity, to improve performance by increasing the number of spindles in a logical drive volume , or to change fault-tolerance (RAID) configurations. With ACU or ACU-XE, an administrator can reconfigure a logical drive to a new RAID level online, without disrupting system operation or causing data loss.
Smart Array Controller Technology: Drive Array Expansion and Extension stripe size migration When an administrator expands the volume capacity of an array, this does nothing to change the stripe size of the data stored within the array. Each RAID level has a default value designed to provide good performance across many types of applications (see table 2). In addition, table 2 shows the range of stripe sizes available per RAID level.
Smart Array Controller Technology: Drive Array Expansion and Extension feedback Please direct comments regarding this communication to the ISS Technology Communications Group at this Internet address: TechCom@HP.com Microsoft, Windows, Win32, Win32s, Win64, Windows NT, and Visual C++ are trademarks of Microsoft Corporation in the U.S. and/or other countries. The information in this document is subject to change without notice. 10/2002 P/N TC021003TB glossary Array – A group of physical drives.
