Microsoft KB Archive/175761

= Dynamic vs. Basic Storage in Windows 2000 =

Article ID: 175761

Article Last Modified on 12/6/2003

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APPLIES TO


 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Datacenter Server
 * Microsoft Windows 2000 Professional Edition
 * Microsoft Windows 2000 Server

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This article was previously published under Q175761



For a Microsoft Windows XP version of this article, see 314343.



SUMMARY
In Windows 2000, a new storage type has been defined and exposed in the new Logical Disk Management snap-in; previous versions of Windows NT used only basic storage:
 * Basic storage uses normal partition tables supported by all versions of Windows, MS-DOS, and Windows NT. A disk initialized for basic storage is called a basic disk. It can hold primary partitions, extended partitions, and logical drives.

Basic volumes include partitions and logical drives, as well as volumes created using Windows NT 4.0 or earlier, such as volume sets, stripe sets, mirror sets, and stripe sets with parity. In Windows 2000, these volumes are called spanned volumes, striped volumes, mirrored volumes, and RAID-5 volumes, respectively.
 * Dynamic storage is supported by Windows 2000. A disk initialized for dynamic storage is called a dynamic disk. It can hold simple volumes, spanned volumes, mirrored volumes, striped volumes, and RAID-5 volumes. With dynamic storage, you can perform disk and volume management without having to restart the operating system.

Upgrading a disk from basic to dynamic can be done from the Disk Management MMC Snap-in. In Programs, go to select Disk Management from Administrative Tools. You may be prompted to upgrade your disks or you can right-click the disk to upgrade it.

WARNING: Upgrading a disk to dynamic storage will render the entire disk unreadable to operating systems other than Windows 2000. This is a one-way process. In order to change back to basic disk format, the drive must be repartitioned.

Storage types are separate from the file system type; a basic or dynamic disk can contain any combination of FAT16, FAT32, and NTFS partitions or volumes.

Windows 2000 accommodates both basic and dynamic storage. A disk system can contain any combination of storage types. However, all volumes on the same disk must use the same storage type.

On a basic disk, a partition is a portion of the disk that functions as a physically separate unit. On a dynamic disk, storage is divided into volumes instead of partitions.



MORE INFORMATION
Dynamic Storage Terms:
 * A volume is a storage unit made from free space on one or more disks. It can be formatted with a file system and assigned a drive letter. Volumes on dynamic disks can have any of the following layouts: simple, spanned, mirrored, striped, or RAID-5.
 * A simple volume uses free space from a single disk. It can be a single region on a disk or consist of multiple, concatenated regions. A simple volume can be extended within the same disk or onto additional disks. If a simple volume is extended across multiple disks, it becomes a spanned volume.
 * A spanned volume is made from free disk space that is linked together from multiple disks (up to a maximum of 32 disks). A spanned volume can be extended onto additional disks. A spanned volume cannot be mirrored.
 * A mirrored volume is a fault-tolerant volume whose data is duplicated on two physical disks. All of the data on one volume is copied to another disk to provide data redundancy. If one of the disks fails, the data can still be accessed from the remaining disk. A mirrored volume cannot be extended. Mirroring is also known as RAID-1.
 * A striped volume is a volume whose data is interleaved across two or more physical disks. The data on this type of volume is allocated alternately and evenly to each of the physical disks. A striped volume cannot be mirrored or extended. Striping is also known as RAID-0.
 * A RAID-5 volume is a fault-tolerant volume whose data is striped across an array of three or more disks. Parity (a calculated value that can be used to reconstruct data after a failure) is also striped across the disk array. If a physical disk fails, the portion of the RAID-5 volume that was on that failed disk can be recreated from the remaining data and the parity. A RAID-5 volume cannot be mirrored or extended.
 * The system volume contains the hardware-specific files (Ntldr, Boot.ini, Ntdetect.com) needed to load Windows NT.
 * The boot volume contains Windows NT operating system files that are located in the %Systemroot% and %Systemroot%\System32 folder.

NOTE: Windows 2000 Advanced Server and Datacenter server shipped from Microsoft do not provide support for dynamic disks in a server cluster (MSCS) environment. The Volume Manager for Windows 2000 add-on product from Veritas can be used to add the dynamic disk features to a server cluster. When the Veritas Volume Manager product is installed on a cluster, Veritas should be the first point of support for cluster issues.

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

237853 Dynamic Disk Configuration Unavailable for Server Cluster Disk Resources

Additional query words: veritas ldm

Keywords: kbinfo kbsetup KB175761

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