Dynamic and Basic Disks
Windows 2000 Server now provides support for dynamic disks as well as basic disks. A dynamic disk is not restricted to four partitions per disk, and several disk-management tasks discussed later in this article can be performed only on dynamic disks. A basic disk is simply partitions and logical drives (and volumes) that were created with Windows NT 4.0 or earlier, such as volume sets, stripe sets, mirror sets, and stripe sets with parity. In Windows 2000, these volumes are now called spanned volumes, striped volumes, mirrored volumes, and RAID-5 volumes.
For Review: Windows NT Disk Solutions
In case you are a little rusty on the storage and fault-tolerant solutions provided in Windows NT, review the following points. This quick review will help you with the content later in this article.
Volume set: A volume set is a collection of partitions that are treated as one partition. This storage solution allows you to combine between 2 and 32 areas of unformatted free disk space to create one logical drive.
Stripe set: A stripe set is like a volume set, but a stripe set combines unformatted free space on 2 to 32 physical drives to create one logical drive. Data is written across the disks in 64K blocks. This process evenly distributes data on the disks and speeds performance. Stripe sets, however, do not provide any inherent fault tolerance.
Mirror set: A mirror set duplicates a partition, and moves the duplicate copy onto another physical disk. In other words, a mirror set maintains two complete copies of the partition at all times. In this case, if one physical disk fails, the data remains on the other physical disk.
Stripe set with parity: A stripe set with parity (RAID 5) requires 3 to 32 physical drives. The data is written in rows across the disk with a parity bit. In the event of a single disk failure, the data can be regenerated using the parity bit.
Dynamic disks in Windows 2000 Server offer you more management flexibility without the partition limitation of basic disks. Dynamic disks can contain an unlimited number of volumes, but they cannot contain partitions or logical drives.
Also, once you upgrade to Windows 2000 Server from Windows NT Server, Windows 2000 Server further limits what you can do with a basic disk. The following list tells you what you can and cannot do with basic disks in Windows 2000 Server:
You can check disk properties and run most administrative tools.
You can view volume and partition properties.
You can change drive letters for disk volumes or partitions.
You can share information and establish security restrictions.
You can create new primary partitions or extended partitions.
You can create and delete logical disks within an extended partition.
You can format a partition, and mark it as active.
You can delete volume sets, stripe sets, and stripe sets with parity.
You can break a mirror set.
You can repair a mirror set or stripe set with parity.
You cannot create new volume sets, stripe sets, mirror sets, or stripe sets with parity.
You cannot extend existing volumes and volume sets.
Basically, Windows 2000 Server allows you to keep your disk configuration when you upgrade from Windows NT 4.0. Although you can manage your basic disks and repair fault-tolerant solutions, you are limited to the current configuration. You really cannot make any significant changes to the disk or establish new volume or stripe sets, and you cannot implement new fault-tolerant solutions.
Windows 2000 has introduced one other item of terminology concerning disk management: online and offline. A disk that is up and running is referred to as online, whereas a disk that has errors that prevent it from running is considered offline. Windows 2000 allows you to make configuration changes to online disks without rebooting the serverin most instances, anyway.