HP Surestore Disk Array FC60 HP SureStore E Disk Array FC60 - (English) Advanc - Page 65

Product Description Capacity Management Features The disk array uses a number of features to manage its disk capacity efficiently. The use of LUNs allow you to divide the total disk capacity into smaller, more flexible partitions. Caching improves disk array performance by using controller RAM to temporarily store data during I/Os. Note Differences in HP-UX and Windows NT/2000 Capacity Management Capacity management on Windows NT and Windows 2000 offers some unique features. Refer to the HP Storage Manager 60 Introduction Guide for information on Windows-specific features. Some of the terms used in the HP Storage Manager 60 software differ from those used here. These terms are also listed in the HP Storage Manager 60 Introduction Guide. LUNs The capacity of the disk array can be divided into entities called LUNs. Individual disks are grouped together to form a LUN. Functionally, each LUN appears to the host operating system as an individual disk drive. Although the LUN appears to the host as an individual disk, the use of multiple disks offers advantages of increased data availability and performance. Data availability is enhanced by using redundant data stored on a separate disk from the original data. The use of multiple disks increases performance by allowing simultaneous access to several disks when reading and writing data. Disk Groups A disk group is a collection of individual disks that share a common role in disk array operation. All disks on the disk array become a member of one of the following disk groups: • LUN group - Each LUN on the disk array has its own disk group. When a disk is included as part of a newly created LUN, the disk becomes a member of the associated disk group. There can be only one LUN in each LUN disk group. Capacity Management Features 65