A dynamic disk is a hard drive which has been formatted to allow capabilities beyond those available when a disk is formatted as a basic disk. Dynamic disk management is a proprietary Microsoft disk management system which became initially available with the release of Microsoft Windows 2000 client and server operating systems. Rather than having a primary partition and an extended partition with logical drives, as is the case with a basic disk, dynamic disk management partitions a hard drive into volumes. Volumes can be increased in size by using available unallocated space on the drive or extended in multiple ways across more than one disk. Extending a dynamic disk can provide increased volume capacity and redundant features, which helps data loss prevention and data recovery.
Most Windows operating systems released after Windows 2000 are capable of using dynamic disks, but there are exceptions which do not support this functionality. Dynamic disk management is compatible with both the Master Boot Record (MBR) and Globally Unique Identifier Partition Table (GPT) partitioning styles. It uses the New Technology File System (NTFS) instead of the File Allocation Table (FAT) file system for volumes. As many as 1000 volumes in a disk group may be created on a dynamic disk, but Microsoft recommends a maximum of 32. Each of these volumes can extend across as many as 32 physical disks.
Partition information for basic disks is stored in a partition table at the beginning of a physical disk, whereas dynamic disks store partition data at the end of the disk in a database file. Basic disks may be converted to dynamic disks, provided there is enough room on the disk to allow the conversion utility to store information, but they cannot be readily converted backward. The use of dynamic disks with dual or multi-boot systems is not recommend due to compatibility issues with alternate operating systems and how Windows stores dynamic disk information in the registry.
Volumes can be extended to become software Redundant Array of Independent Disks-5 (RAID-5) volumes, which provide excellent fault tolerance by stripping small units of both data and parity across at least 3 disks. Mirrored extensions of dynamic disks allow two complete, active copies of a volume to exist and be updated simultaneously. Spanned, stripped, and simple volume extensions are also available but do not provide fault tolerance.
Although Windows client operating systems have the capability of utilizing dynamic disks, they are typically used in and better suited for server environments. Major advantages of using this type of disk management system are the capabilities of disk storage growth, redundancy, and flexibility when working with physical disks. All of these features are frequently used to resolve issues in server situations.