WINDOWS 1002000 PROFESSIONAL RESOURCE KIT [Electronic resources] نسخه متنی

Basic and Dynamic Disks

Microsoft® Windows® 2000 offers two types of disk storage configurations: basic disk and dynamic disk. Basic disk is similar to the disk structures used in Microsoft® Windows NT®. Dynamic disk is new to Windows 2000. By default, Windows 2000 initializes hard disks as basic disk.

The Disk Administrator tool found in Microsoft® Windows NT® version 4.0 and earlier has been replaced in Windows 2000 with the Disk Management snap-in for the Microsoft Management Console (MMC). Disk Management supports both basic and dynamic disks. You can use the upgrade wizard in Disk Management to convert basic disks to dynamic disks.

You can use both basic and dynamic disks on the same computer system, and with any combination of file systems (file allocation table [FAT], including FAT16 and FAT32, and NTFS file system). However, all volumes on a physical disk must be either basic or dynamic.

You can upgrade from basic to dynamic storage at any time. Any changes made to your disk are immediately available in Windows 2000—you do not need to quit Disk Management to save them or restart your computer to implement them. However, if you upgrade the startup disk to dynamic, or if a volume or partition is in use on the disk that you are upgrading, the computer must be restarted for the upgrade to succeed.

Terms

To help you understand the differences between basic disk and dynamic disk, a set of definitions are provided.

Basic Disk

A basic disk is a physical disk that contains primary partitions and/or extended partitions with logical drives used by Windows 2000 and all versions of Windows NT. Basic disks can also contain volume or striped sets that were created using Windows NT 4.0 or earlier. As long as a compatible file format is used, basic disks can be accessed by Microsoft® MS-DOS®, Microsoft® Windows® 95, Microsoft® Windows® 98, and all versions of Windows NT.

Since Windows 2000 automatically initializes disks as basic, you can troubleshoot partitions and volumes using the same methods as in Windows NT.

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FAT32 is new in Windows 2000. Disk troubleshooting tools from Windows NT will likely not recognize FAT32 boot sectors and may cause problems with FAT32-formatted volumes. If FAT32 is used on your computer, be sure to use a disk troubleshooting tool designed for Windows 2000 that recognizes this file format.

New or empty disks can be initialized as either basic or dynamic after the hardware installation is complete.

Basic Volume

A basic volume is a volume on a basic disk. Basic volumes include primary partitions, logical drives within extended partitions, as well as volume or striped sets created using Windows NT 4.0 or earlier. You cannot create basic volumes on dynamic disks.

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Creating new fault-tolerant (FT) sets, such as mirrored and redundant array of independent disks (RAID) Level 5 (also known as striped with parity) volumes, is only available on computers running Windows 2000 Server. The disk must be upgraded to dynamic disk before these volumes can be created. You can, however, use a computer running Windows 2000 Professional to create mirrored and RAID-5 volumes on a remote computer running Windows 2000 Server.

Dynamic Disk

A dynamic disk is a physical disk that has been upgraded by and is managed with Disk Management. Dynamic disks do not use partitions or logical drives. They can contain only dynamic volumes created by Disk Management. Only computers running Windows 2000 can access dynamic volumes.

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Disks that have been upgraded from basic to dynamic disk still contain references to partitions in the partition table of the MBR. However, the MBR's reference to these partitions identifies the partition types as dynamic, indicating to Windows 2000 that the disk configuration data is now maintained in the disk management database at the end of the disk. Furthermore, any new changes made to the disk, such as deleting existing or creating additional volumes, are not recorded in the partition table.

Dynamic disks use dynamic volumes to subdivide physical disks into one or more drives enumerated by letters of the alphabet.

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Volumes formatted with NTFS can also be represented as volume mount points. For more information about volume mount points, see "File Systems" in this book.

Disk configuration data is contained in a disk management database stored in the last 1 megabyte (MB) of space at the end of the disk. Since dynamic disks do not use the traditional disk organization scheme of partitions and logical volumes, they cannot be directly accessed by MS-DOS, Windows 95, Windows 98, or any versions of Windows NT. Shared folders on dynamic disks, however, are available to computers running all of these operating systems.

Dynamic Volume

A dynamic volume is a logical volume that is created on a dynamic disk using Disk Management. Dynamic volume types include simple, spanned, and striped, although Windows 2000 Server also supports the FT volume types (mirrored and RAID-5). You cannot create dynamic volumes on basic disks. Dynamic volumes are not supported on portable computers or removable media.

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Dynamic volumes that were upgraded from basic disk partitions cannot be extended. This specifically includes the system volume, which contains hardware-specific files needed to start Windows 2000, and the boot volume, which contains the Windows 2000 system files required for startup. Only volumes created after the disk was upgraded to dynamic can be extended.

Partitions and Volumes

When you upgrade to dynamic disk, existing partitions and logical volumes are converted into dynamic volumes. Table 32.1 illustrates the translation of terms between basic and dynamic disk structures.

Table 32.1 Translation of Terms Between Basic and Dynamic Disk

Features of Basic Disk

You can use partitions on a basic disk just as you did with Microsoft® Windows NT® Workstation version 4.0, but you do not need to commit changes to save them or to restart your computer to make the changes effective. Changes made by Disk Management are implemented immediately. Unless you are making a change that affects existing files on the disk, the system executes your change without confirmation.

You can create up to four partitions in the free space on a physical hard disk; one of these can be an extended partition. You can use the free space in the extended partition to create one or more logical drives. You cannot use basic disk to create any kind of multiple volume sets or FT volumes.

You can perform the following tasks only on a basic disk:

Create and delete primary and extended partitions.

Create and delete logical drives within an extended partition.

Format a partition and mark it as active.

Delete volume, striped, mirror, or stripe sets with parity.

Certain legacy functions are no longer available on basic disks because multiple-disk storage systems need to use dynamic disks. Disk Management supports legacy volume sets and striped sets, but it does not allow you to create new ones. For example, you cannot create volume or striped sets or extend volumes and volume sets on a basic disk.

While you cannot create new multiple disk sets on basic disks, you can delete them. Be sure to back up all the information on the set before you delete it.

To establish a new spanned or striped volume, first upgrade the disk to dynamic disk. To convert an existing volume or striped set, upgrade the physical disks on which the set resides to dynamic disk.

Features of Dynamic Disk

Disk Management is very flexible. The number of volumes that you can create on a physical hard disk is limited only by the amount of available free space on the disk. You can also create volumes that span two or more disks and that, if you are running Windows 2000 Server, are fault tolerant.

You can perform the following tasks only on a dynamic disk:

Create and delete simple, spanned, and striped volumes.

Extend a simple or spanned volume.

Reactivate a missing or offline disk.

Dynamic disks are not supported on portable computers. 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 upgrade the disk to dynamic.

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On some older and non-Advanced Configuration and Power Interface (ACPI)-compliant portable computers, you might be able to upgrade to dynamic disk, but it is neither recommended nor supported. Dynamic disk is not supported on removable disks, nor on disks using Universal Serial Bus (USB) or IEEE 1394 (also called FireWire) interfaces.

The limitations of dynamic volumes occur in the following situations:

When installing Windows 2000 If a dynamic volume is created from unallocated space on a dynamic disk, you cannot install Windows 2000 on that volume.

The setup limitation occurs because Windows 2000 Setup uses BIOS calls that only recognize volumes listed in the partition table. Only basic disk partitions, as well as simple volumes of dynamic disk that were upgraded from basic disk partitions, appear in the partition table. Dynamic disk does not use the partition table to manage its volumes, so new dynamic volumes are not registered in the partition table as they are created. Windows 2000 must be installed on a volume that is correctly represented in the partition table.

When extending a volume You cannot extend either the system volume or the boot volume in dynamic disk. Neither can be part of a spanned volume, since Windows 2000 considers extended volumes to be the same as spanned volumes.

Windows 2000 cannot extend any dynamic volume that existed as a basic volume before the dynamic disk upgrade, and the system and boot volumes (which might be one and the same) are likely the same volumes that existed under basic disk. Upgraded simple volumes in dynamic disk are still hard-linked to the partition table and must match the listing found there. Extending a dynamic volume changes its size, but since dynamic disk does not record volume changes to the partition table, upgraded volumes cannot be modified in this manner. The only dynamic volumes that can be extended are simple volumes created after the disk was upgraded to dynamic disk. If you want to extend an upgraded non-boot or non-system volume, delete the upgraded volume and recreate it under dynamic disk. You can use Windows 2000 Backup to save all the data on the volume and restore it after the volume has been recreated. Use Disk Management to assign the new volume the same drive letter or volume mount point as the original volume to ensure that all drive letter connections continue to work after the change.

Features Common to Both Basic and Dynamic Disks

You can perform the following tasks on both basic and dynamic disks:

Check disk properties such as capacity, available free space, and current status.

View volume and partition properties such as size, drive-letter assignment, label, type, and file system.

Establish drive-letter assignments for disk volumes or partitions, and for CD-ROM devices.

Establish disk sharing and security arrangements for a volume or partition.

Upgrade a basic disk to dynamic or revert a dynamic disk to basic.

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You can upgrade a basic disk to dynamic disk without loss of data. However, reverting a dynamic disk back to basic disk requires that you remove all volumes prior to the conversion. If you want to keep your data, you must back it up or move it to another volume. Once the volume is reverted back to basic disk, you can create a new partition using the same drive letter or volume mount point that was used with the dynamic volume and restore the data.