Basic and Dynamic Disks

As you probably know, Windows NT supports four primary partitions per physical hard disk, one of which can be an extended partition. Of course, you can create logical drives within the extended partition. Windows 2000 (Win2K) follows the same strategy: You can have a maximum of four primary partitions, one of which can be an extended partition with logical drives. However, Win2K supports two new disk configuration types—basic disk and dynamic disk—which you must understand to effectively configure and troubleshoot Win2K disk storage.

Basic Disk

A Win2K basic disk, which is similar to the disk configuration we're used to in NT, is a physical disk with primary and extended partitions. As long as you use an appropriate format, Win2K, NT, Windows 9x, and DOS can access basic disks. Unlike in NT, you don’t need to commit changes or restart your computer to get Disk Management changes to take effect.

Dynamic Disk

A Win2K dynamic disk is a physical disk that doesn't use partitions or logical drives. Instead, it contains only dynamic volumes that you create in the Disk Management console. Regardless of what format you use for the file system, only Win2K computers can access dynamic volumes directly. However, computers that aren't running Win2K can access the dynamic volumes remotely when connected to the shared folders over the network. In NT, what we call sets (e.g., mirrored sets, striped sets) are in Win2K called volumes (e.g., mirrored volumes, striped volumes).

With dynamic disks, we can create fault-tolerant volumes such as striped, mirrored, and RAID-5 volumes. In addition, we can extend volumes and make changes to the disk without rebooting the computer. If you want to take advantage of these features, especially software fault- tolerant features, you must upgrade to dynamic disk.

Upgrading to Dynamic Disk

You use Win2K's Disk Management to upgrade a basic disk to a dynamic disk. Click Start and go to Programs, Administrative Tools, Computer Management. You’ll find Disk Management under Storage, as Screen 1 shows. Click the gray area where you see the disk icon and the word Basic. Right-click and select Upgrade to Dynamic Disk. Note that you can’t dual-boot to another OS if you upgrade to dynamic disk, which typically isn't a big deal for servers, but it's something to think about for Windows 2000 Professional (Win2K Pro) machines.

For all practical purposes, upgrading to a dynamic disk is a one-way process. Although it's possible to convert a dynamic disk with volumes to a basic disk, you'll lose all your data. Therefore, you must first save your data, convert the disk to basic, and then restore your data.

Comparing Basic Disk to Dynamic Disk

When you install Win2K on a computer, the system automatically configures the hard disks as basic disks. You can convert a basic disk to a dynamic disk using Disk Management, but you can't extend a basic disk. In other words, you can only extend volumes you created after you converted the disk to a dynamic disk.

You can create primary and extended partitions on a basic disk, and, as I mentioned earlier, you can create an extended partition with logical drives on a basic disk. A dynamic disk can contain simple, spanned, mirrored, striped, and RAID-5 volumes. You can also extend a simple or spanned volume on a dynamic disk.

Win2K doesn't support dynamic disks on laptops, and, unless you're using an older machine that's not Advanced Configuration and Power Interface (ACPI)-compliant, the Upgrade to Dynamic Disk option won’t be available. Dynamic disks have some additional limitations. You can’t install Win2K on a dynamic volume you created from raw space on a dynamic disk. You can install Win2K on a dynamic volume that you upgraded from a basic disk, but you can’t extend either the system or the boot partition. Any troubleshooting tools that are unable to read the dynamic Disk Management database will work only on a basic disk.

You can use NTFS, FAT32, or FAT16 on a basic or a dynamic disk. Because the upgrade from basic to dynamic is per physical disk, all volumes on a physical disk must be either basic or dynamic. As I mentioned earlier, you don’t need to save changes in Disk Management (as you do in NT’s Disk Administrator) or restart your computer when you upgrade from a basic to a dynamic disk. However, if you upgrade your startup disk or upgrade a volume or partition, you must restart your computer.

Basic and dynamic disks are a new way of looking at hard disk configuration. If you're migrating to Win2K from NT, the dynamic disk concept might seem strange initially, but you’ll find that once you understand the differences and the pros and cons, working with dynamic disks is not complicated. (See also, "Choosing Basic vs. Dynamic Disk Storage for Windows Servers").