After you convert a basic disk to a dynamic disk, you cannot change the
dynamic volumes back to partitions. Instead, you must delete all dynamic
volumes on the disk and then use the Convert To Basic Disk command. If you
want to keep your data, you must first back it up or move it to another
volume. .
Before you convert disks, close any programs that are running on those disks.
For the conversion to succeed, any master boot record (MBR) disks to be
converted must contain at least 1 MB of space for the dynamic disk database.
Windows 2000 and Windows XP Professional automatically reserve this space
when creating partitions or volumes on a disk, but disks with partitions or
volumes created by other operating systems may not have this space available.
(This space may exist even if it is not visible in Disk Management.)
Once converted, a dynamic disk will not contain basic volumes (primary
partitions or logical drives), nor can it be accessed by MS-DOS, Windows 95,
Windows 98, Windows Millennium Edition, Windows NT, or Windows XP Home
Edition operating systems. Dynamic disks can only be accessed with Windows
2000 or Windows XP Professional.
When you convert a basic disk to a dynamic disk, any existing partitions or
logical drives on the basic disk become simple volumes on the dynamic disk.
Do not convert disks to dynamic that contain multiple installations of
Windows 2000 or Windows XP Professional. When a disk is converted to dynamic,
the partition entries for all partitions on the disk are removed, except for
the system and boot volumes of the currently running operating system.
Converting a disk to dynamic does not check for other installations of
Windows, and deletes the partition entries for any other boot volumes on the
disk. In addition, the volume-related registry entries in the second
installation become outdated, and as a result you can no longer start that
operating system.
More on 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 XP. However, you can use a
computer running Windows XP Professional to 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 per disk group, although the recommended number of dynamic
volumes is 32 or less per disk.
When using dynamic volumes, the following limitations apply:
When installing Windows XP Professional. If a dynamic volume is created from
unallocated space on a dynamic disk, you cannot install Windows XP
Professional on that volume. However, you can extend the volume (if it is a
simple or spanned volume). This setup limitation occurs because Windows XP
Professional Setup recognizes only dynamic volumes that have an entry in the
partition table.
Portable computers. 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.
Dual-boot computers.
Dynamic volumes (and the data they contain) cannot be accessed by, or
created on, computers running MS-DOS, Windows 95, Windows 98, Windows
Millennium Edition, Windows NT 4.0, or Windows XP Home Edition that are
configured to dual-boot with Windows XP Professional or Windows XP. If you
want computers running these operating systems to be able to access the data,
store the data on basic volumes instead.
When extending a volume. If a basic volume is converted to dynamic (by
converting a basic disk to dynamic), it may or may not have an entry in the
partition table depending on whether that volume was a system or boot
partition. If the converted volume was a system or boot partition it retains
an entry in the partition table. You can install Windows XP Professional on
the volume, but you cannot extend it. If the converted volume was not a
system or boot volume it does not have an entry in the partition table. You
cannot install Windows XP Professional on the volume, but you can extend it.
On Windows 2000, volumes converted from partitions have an entry in the
partition table. On Windows XP Professional, volumes converted from
partitions do not have an entry in the partition table unless the partitions
were system or boot partitions. In Disk Management, you can see if a volume
has an entry in the partition table by right-clicking the volume. If Extend
Volume is disabled, the volume has an entry in the partition table.
You can install Windows XP Professional only on simple and mirrored dynamic
volumes, and these volumes must have entries in the partition table (which
means that these volumes were system or boot volumes).
