Extending Volumes on Converted Dynamic Disks in Windows 2000

This article explains how Microsoft Windows 2000 handles volume extensions following the conversion of basic disks to dynamic disks. When upgrading storage in Windows 2000, converting a basic disk to a dynamic disk transforms existing partitions into simple volumes, which introduces specific capabilities and strict limitations regarding how and when these volumes can be expanded.

Conversion from Basic to Dynamic

In Windows 2000, converting a basic disk to a dynamic disk is a non-destructive process managed by the Logical Disk Manager (LDM). During this transition:

  • Existing primary partitions and logical drives are automatically converted into dynamic simple volumes.
  • The disk's partition table is retained to ensure bootability, while the LDM database is written to the final 1 MB of the physical disk to track dynamic volume structures.
  • The conversion is strictly one-way; dynamic disks cannot be reverted back to basic disks without deleting every volume and erasing all data.

Rules for Extending Converted Volumes

Once a basic disk is converted to dynamic, the ability to extend the resulting simple volumes depends directly on the volume type and file system:

  • NTFS Requirement: Only volumes formatted with the NTFS file system can be extended. Any simple volume formatted with FAT or FAT32 cannot be extended, regardless of available unallocated space.
  • System and Boot Volume Restrictions: In Windows 2000, any simple volume that hosts the system partition (containing hardware-specific files like NTLDR) or the boot partition (containing the \WINNT directory) cannot be extended. Even after conversion to a dynamic disk, these volumes must remain at their original size.
  • Data Volumes: Converted simple volumes that do not contain system or boot files can be extended into contiguous or non-contiguous unallocated space on the same physical dynamic disk.

Spanning Across Multiple Disks

Windows 2000 allows a converted, non-boot NTFS simple volume to be extended onto unallocated space located on other dynamic disks.

When a simple volume is extended onto one or more additional physical dynamic disks, it automatically converts into a spanned volume. While this combines fragmented storage across physical drives into a single drive letter, it carries inherent operational risks:

  • Spanned volumes cannot be mirrored or striped after creation.
  • If any single physical disk within the spanned volume fails, the entire volume becomes inaccessible, leading to complete data loss across all linked segments.

Management Tools and Limitations

Volume extensions on dynamic disks in Windows 2000 are performed using the graphical Disk Management snap-in within the Computer Management console (diskmgmt.msc) or via the command-line utility provided in the Windows 2000 Resource Kit.

Windows 2000 does not support volume shrinking. Once a volume has been extended into additional unallocated space, the allocated space cannot be reduced without backing up the data, deleting the volume entirely, and recreating it with smaller dimensions.