Dynamic Disks

In Windows Server operating systems, a dynamic disk does not use partitions or logical drives, and the Master Boot Record (MBR) is not used. Instead, the basic partition table is modified and any partition table entries from the MBR are added as part of the Logical Disk Manager (LDR) database that stores information at the end of each dynamic disk.

Dynamic disks can contain a virtually unlimited number of volumes, so you are not restricted to four volumes per disk as you are with basic disks. However, in practice you should limit the number of volumes to 32 for each dynamic disk. Dynamic disks do not have the same limitations as basic disks, eg: you can extend a dynamic disk without needing to reboot.

Dynamic disks are associated with disk groups, which are sets of disks that are managed as a collection. All dynamic disks in a computer are members of the same disk group and each disk in a disk group stores the same configuration data. This is stored in the 1MB LDR region at the end of each dynamic disk. Dynamic disks support five types of volumes: simple, spanned, mirrored, striped and RAID-5. We’ll look at these in more detail later.

Although only operating systems from Windows Server and Clients such as Windows XP, 7 or 8 can directly access dynamic volumes on hard disks that are physically connected to the computer. Computers running other operating systems such as Linux or Mac can access dynamic volumes remotely when they connect to shared folders over a network.

Dynamic disks are only supported on computers that use the Small Computer System Interface (SCSI), Fibre Channel, Serial Storage Architecture (SSA), Integrated Drive Electronics (IDE), Enhanced IDE (EIDE), Ultra Direct Memory Access (DMA) or Serial Advanced Technology Attachment (SATA) interfaces.

Windows Server does not support dynamic disks on mobile PCs (laptops or notebooks), removable disks (including USB and FireWire devices) or on older desktop machines that are not Advanced Configuration and Power Interface (ACPI)-compliant.

You can install Windows Server on a dynamic volume that you converted from a basic disk, but you cannot extend either the system or the boot volume on a dynamic disk. Any troubleshooting tools that cannot read the dynamic disk management database work only on basic disks. You can format partitions with the FAT16, FAT32 or NTFS on a basic or a dynamic disk, but you can only format a dynamic volume as NTFS from the Disk Management console. You can use Windows Server Explorer to format a dynamic volume as FAT or FAT32.

On desktop operating systems, such as Windows 7, dynamic disks provide support for advanced disk configurations, such as disk striping and disk spanning. On Windows Server computers, dynamic disks provide support for fault-tolerant configurations, such as disk mirroring and disk striping with parity (also known as RAID-5).

Next: Partitions