Understand the differences between basic and dynamic disks

Windows 2000 introduced the concepts of basic disks and dynamic disks and added them to the Windows system administrator's arsenal of tools. What's the difference between the two? Let's look at both types of disks, examine the distinctions between them, and discuss how you can most effectively use each type.

The most obvious difference between basic and dynamic disks lies in operating system support. While all versions of Windows--even DOS--support basic disks, we can't say the same for dynamic disks. Only later versions of Windows, including Windows 2000, Windows XP, and Windows Server 2003, support dynamic disks.

Regardless of the disk type--basic or dynamic--you can use any file system you want, including FAT or NTFS. However, you can make volume changes to dynamic disks without having to reboot the system.

You can convert a disk from basic to dynamic. However, it's important to understand that this isn't a two-way street. Once you've converted a disk to be dynamic, you can't revert to basic without first wiping and re-creating the volume.

Let's take a closer look at these two types of disks.

Basic disks
As the name implies, basic disks are the ones that IT pros are most familiar with, and the typical terms and technologies apply. For example, basic disks contain primary partitions, extended partitions, and logical drives.

Using primary partitions, Windows NT-based systems can also support striping and software RAID sets. However, Windows 2000, Windows XP, and Windows Server 2003 don't support striping and software RAID sets for basic disks.

Dynamic disks
Dynamic disks support new features and sport new terminology. Here's a look at the different types of volumes you can create with a dynamic disk:

• Simple volumes use space from a single disk or a hardware array volume.
• Spanned volumes are non-fault-tolerant disk sets that use free space from multiple disks in the system.
• Striped volumes are non-fault-tolerant disk sets (RAID 0) that stripe data across multiple disks in the system.
• Mirrored volumes are fault-tolerant disk sets (RAID 1) that mirror data from one disk to another.
• RAID 5 volumes are fault-tolerant disk sets that stripe data across three or more disks and include parity information.

Windows XP doesn't support mirrored volumes or RAID 5 volumes.