HP 127695-B21 Smart Array Controller Technology: Drive Array Expansion and Ext - Page 6

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. An administrator can perform volume extensions using ACU or ACU-XE if the system uses basic disks. The administrator can use the new space on the logical drive for an additional partition, or can grow the existing partition by using a third-party software utility such as PowerQuest's Partition Magic. Windows 2000 supports basic and dynamic disks, with dynamic disks being the default partition system. A Windows 2000 dynamic disk is a physical disk that doesn't use static partitions or logical drives. Instead, it contains only dynamic volumes that can span multiple partitions. Dynamic disks are created in the Disk Management console of Windows 2000 and contain database tables at the beginning and the end of the dynamic volume to recognize the partition boundaries. Because this database may still exist even after a logical drive is deleted, an administrator must be careful when performing volume extension on a dynamic drive. The best way to grow a volume size in Windows 2000 is to take advantage of this dynamic disk functionality, rather than performing a volume extension in ACU or ACU-XE. Because a dynamic disk can span multiple partitions on separate logical drives, an administrator can create a completely new logical drive when free space exists. Then the administrator can create a new partition on the logical drive and add it as a segment to the existing volume (this is what Microsoft calls expansion4). This functionally is the same as extending the volume size in ACU or ACU-XE. If an administrator desires to use ACU or ACU-XE to extend a volume, the administrator should determine whether the drives are pristine - that is, the physical drives have never been used for any other dynamic disk. If so, the administrator should download and apply the Microsoft Service Pack 3. This ensures proper compatibility between Microsoft dynamic disks and logical volume extension using Smart Array Controllers. If the administrator is trying to extend a volume of dynamic disks on previously used physical drives, the database used for a dynamic disk may still exist even after the logical drive is deleted. In this case, when an administrator performs volume extension, the OS may see this old database. In this case, the partition on the logical drive may be marked as a foreign disk and become unusable. 4 Microsoft expansion refers to adding partitions to a volume using dynamic disks and growing the size of that volume. 6