Dynamic disks and volumes
Updated: January 21, 2005
Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2
Dynamic disks and volumes
Dynamic disks provide features that basic disks do not, such as the ability to create volumes that span multiple disks (spanned and striped volumes), and the ability to create fault tolerant volumes (mirrored and RAID-5 volumes). All volumes on dynamic disks are known as dynamic volumes.
There are five types of dynamic volumes: simple, spanned, striped, mirrored, and RAID-5. Mirrored and RAID-5 volumes are fault tolerant and are available only on computers running Windows 2000 Server, Windows 2000 Advanced Server, Windows 2000 Datacenter Server, or Windows Server 2003 operating systems. You can, however, use a computer running Windows XP Professional to remotely create mirrored and RAID-5 volumes on these operating systems.
Regardless of whether the dynamic disk uses the master boot record (MBR) or GUID partition table (GPT) partition style, you can create up to 2,000 dynamic volumes, although the recommended number of dynamic volumes is 32 or less.
For information about how to manage dynamic volumes, see Manage Dynamic Volumes.
Considerations when using dynamic disks and dynamic volumes
When using dynamic volumes, the following considerations apply:
Installing Windows Server 2003 operating systems. You can perform a fresh installation of Windows Server 2003 operating systems on a dynamic volume only if that volume was converted from a basic boot volume or basic system volume. If the dynamic volume was created from unallocated space on a dynamic disk, you cannot install Windows Server 2003 operating systems on that volume. This setup limitation occurs because Setup for Windows Server 2003 recognizes only dynamic volumes that have an entry in the partition table. You can, however, extend the volume (if it is a simple or spanned volume).
Do not convert basic disks to dynamic disks if they contain multiple installations of Windows 2000, Windows XP Professional, or Windows Server 2003 operating systems. After the conversion, it is unlikely that you will be able to start the computer using that operating system.
For information about basic volumes, see Basic disks and volumes.
Portable computers and removable media. Dynamic disks are not supported on portable computers, removable disks, detachable disks that use Universal Serial Bus (USB) or IEEE 1394 (also called FireWire) interfaces, or on disks connected to shared SCSI buses. If you are using a portable computer and right-click a disk in the graphical or list view in Disk Management, you will not see the option to convert the disk to dynamic.
Boot and system partitions. You can convert a basic disk containing the system or boot partitions to a dynamic disk. After the disk is converted, these partitions become simple system or boot volumes (after restarting the computer). You cannot mark an existing dynamic volume as active. You can convert a basic disk containing the boot partition (which contains the operating system) to a dynamic disk. After the disk is converted, the boot partition becomes a simple boot volume (after restarting the computer).
Mirroring the boot and system volumes. If you convert the disk containing the boot and system partitions to a dynamic disk, you can mirror the boot and system volumes onto another dynamic disk. Then, if the disk containing the boot and system volumes fails, you can start the computer from the disk containing the mirrors of these volumes. For more information, see Create and test a mirrored system or boot volume.
Converting dynamic disks to basic disks. After you convert a basic disk into a dynamic disk, you cannot change the dynamic volumes back to partitions. Instead, you must move or back up your data, delete all dynamic volumes on the disk and then convert the disk. For more information, see Change a dynamic disk back to a basic disk.
Shadow copies storage area. If you are using a basic disk as a storage area for shadow copies and you intend to convert the disk into a dynamic disk, it is important to take the following precaution to avoid data loss. If the disk is a non-boot volume and is a different volume from where the original files reside, you must first dismount and take offline the volume containing the original files before you convert the disk containing shadow copies to a dynamic disk. You must bring the volume containing the original files back online within 20 minutes, otherwise, you will lose the data stored in the existing shadow copies. If the shadow copies are located on a boot volume, you can convert the disk to dynamic without losing shadow copies.
You can use the mountvol command with the /p option to dismount the volume and take it offline. You can mount the volume and bring it online using the mountvol command or the Disk Management snap-in.