Windows

Taking advantage of Windows NT Disk Administrator

In this Daily Feature, Troy Thompson provides an overview of Windows NT Disk Administrator, the primary tool for disk management in Windows NT Server and Windows NT Workstation.

The Windows NT Disk Administrator is the primary tool for disk management in Windows NT Server and Windows NT Workstation. The Disk Administrator takes the functionality of some of the old DOS-based disk utilities—such as Fdisk and the Microsoft LANManager Fault Tolerance character applications—and combines them into a single graphical interface.

In this Daily Feature, I’ll examine the functions you can perform with Disk Administrator. As you’ll see, Disk Administrator lets you:
  • Create and delete partitions on a hard disk and logical drives within an extended partition.
  • Format and label volumes.
  • Read status information about disks, such as the partition sizes and the amount of free space available for creating additional partitions.
  • Read status information about Windows NT volumes, such as the drive-letter assignment, volume label, file system type, and size.
  • Make and change drive-letter assignments for hard disk volumes as well as CD-ROM devices.
  • Create and delete volume sets.
  • Extend volumes and volume sets.
  • Create and delete stripe sets with or without parity.
  • Regenerate a missing or failed member of a stripe set with parity.
  • Establish or break disk-mirror sets.

Partitioning the internal hard disk on a new computer is done during initial setup when you load the Windows NT operating software. You make changes to that disk or partition an additional new hard disk by using the Disk Administrator program. You can’t use Disk Administrator to further partition the system partition, because it contains files required to operate Windows NT Server.

Starting Disk Administrator
You can open Disk Administrator only if you are a member of the Administrators group. To access Disk Administrator, select Start | Programs | Administrative Tools, then click Disk Administrator. The first time you use Disk Administrator, you’ll see a message stating that your system configuration will be updated. Once you click OK, you’ll see another message indicating that there is no signature file on Disk 0. You must click Yes to write a signature to the disk. Otherwise, the disk will be marked offline and inaccessible to Disk Administrator. This process is safe and will not destroy or damage your disks.

Once you’re in Disk Administrator, you’ll see a graphical representation of all physical disks connected to your computer along with their partitions. At the bottom of the window is a status bar that provides basic information about the partitions. A color-coded legend on top of the status bar shows what the different partition colors and patterns represent, as shown in Figure A.

Figure A
A color-coded legend tells you what the partition colors and patterns represent.


You can show or hide the toolbar, status bar, and legend by using the Options menu. By default, the Disk Administrator toolbar includes buttons for Volume and Disk Configuration views, and for Properties, which opens the Properties dialog box for a volume you select. You can add other buttons to the toolbar. When the toolbar, status bar, or legend is on screen, a check mark appears next to the corresponding choice.

Changing the look
Colors and patterns are used to distinguish these items: primary partition, logical drive, stripe set, stripe set with parity, mirror set, and volume set. The default pattern is solid.

You can change the colors and patterns used to distinguish your disk volumes. Perform the following steps:
  1. On the Options menu, click Colors And Patterns.
  2. Select the item you want to change.
  3. Select a new color in Colors.
  4. Select a new pattern in Patterns, then click OK.

You can also change how the disk sizes are displayed. Changing the display can be helpful when you have several disks with a wide range of capacities. The total lengths of the bars used to represent disks are generally proportional to the size of the disk. However, the total length of a single disk bar is never less than 25 percent of the total length of the largest disk bar. To change this display, first choose Disk Display from the Options menu. Then, click Size Disks Based On Actual Size or Size All Disks Equally.

In addition, you can change how regions are displayed. From the Options menu, select Region Display to open the dialog box shown in Figure B.

Figure B
Use this dialog box to specify the region display.


In the Which Disk area, choose one of the following:
  • Click All Disks to specify the region display for all disks connected to your computer.
  • Click For Disk to select the number of the disk you want to change.

Specify the relative display size of partitions by choosing one of the following:
  • Size Regions Based On Actual Size
  • Size All Regions Equally
  • Let Disk Administrator Decide How To Size Regions

Repeat until all the partition displays are configured the way you want them, and then click OK.

You can click Reset All to let Disk Administrator decide how to display all the disks. Partitions are shown as being proportionate to each other within a single disk bar.

Creating a primary partition
To create a primary partition, first select an area of free space on a disk. Next, select Create from the Partition menu. If the space you selected is not the first primary partition created on the disk, a message appears prompting you to confirm the creation of another primary partition, because the partition could not be recognized by MS-DOS. Click Yes.

At this point, Disk Administrator will display the minimum and maximum sizes for the primary partition. In the Create Partition Of Size area, type the size of the primary partition you want to create, then click OK. If the partition size is greater than 2 GB, you’ll see a message warning you that it will not be accessible from DOS.

The new unformatted primary partition will be assigned a drive letter. You must choose Commit Changes Now from the Partition menu to save your changes.

A disk can have up to four primary partitions, including the extended partition. To create an extended partition, select an area of free space on a disk. Then, choose Create Extended from the Partition menu. Disk Administrator will display the minimum and maximum sizes for the extended partition. Type the size of the extended partition you want to create, then click OK. Again, you must choose Commit Changes Now from the Partition menu to save your changes.

Only one extended partition can be created per disk. You can use the free space in the extended partition to create multiple logical drives, or you can use all or part of it when creating volume sets or other kinds of volumes for fault-tolerance purposes.

To create logical drives in an extended partition, first select an area of free space in an extended partition. Then, select Create from the Partition menu. Disk Administrator will display the minimum and maximum sizes for the logical drive. At this point, type the size of the logical drive you want to create and click OK. Once more, you must choose Commit Changes Now from the Partition menu to save your changes.

Formatting a partition and labeling the volume
After you’ve created a partition and committed the changes, you can format the partition. Begin by selecting the partition you wish to format. Then, choose Format from the Tools menu. When the Format dialog box shown in Figure C appears, choose FAT or NTFS for the file system and specify a volume label, if you wish.

Figure C
You may specify a volume label, although this step is optional.


Quick Format will allow you to skip scanning for bad sectors in the partition. This option is not available when formatting mirror sets and stripe sets with parity.

Now, click Enable Compression to compress the folders and files that are added to the volume. This option is available if the partition is being formatted with NTFS. Click Start to initiate the format request. A message warns you that all data on the disk will be erased. Click OK.

When the Format Complete message appears, click OK. It is possible to cancel the formatting at any time during the process; however, clicking Cancel will not necessarily restore a volume to its previous state.

When you want to reformat an existing NTFS partition containing Windows NT, you must first back up the information on the partition. If Windows NT system files are installed on the partition, you cannot delete it from within Disk Administrator, nor can you reformat the partition using Format. Instead, you must use the setup program from your installation media.

When Windows NT setup asks you to select the partition on which you would like to install, select the NTFS partition and press D to delete the partition.

Either continue using the setup program to re-create and format the partition, or quit the setup program and use the MS-DOS Fdisk and Format commands to complete the process.

Marking a partition as active and assigning drive letters
There can only be one active system partition at a time. On Intel-based computers, the system partition must be a primary partition that has been marked as active for startup purposes, and it must be located on the disk that the computer accesses when starting up the system.

Partitions on a RISC-based computer are not marked active. They will be configured by a hardware configuration program supplied by the manufacturer. On RISC-based computers, the system partition must be formatted for the FAT file system. On either type of computer, the system partition can never be part of a stripe set or volume set.

To mark a partition as active on an x86-based computer, select the primary partition that contains the startup files for the operating system you want to activate. Then, choose Mark Active from the Partition menu. A message will appear advising you that the partition has been marked active and that the operating system on that partition will be started when you restart your computer. Click OK to continue.

To assign a drive letter, first select the partition or logical drive whose drive letter you want to assign. From the Tools menu, choose Assign Drive Letter. Then, in the Assign Drive Letter dialog box, click Assign Drive Letter and select the appropriate letter. Click OK to continue.

You should be careful when making drive-letter assignments, because many MS-DOS and Windows programs make references to a specific drive letter. There may be entries in the Registry that refer to a specific drive. Also, an error message may appear when you’re attempting to assign a letter to a CD-ROM drive if it is in use.

Changes in drive-letter assignments are effective immediately; you don’t have to choose Commit Changes Now.

Deleting partitions, volumes, and logical drives
Keep in mind that when you delete partitions, volumes, or drives, the changes will not be made until you commit the changes from the Partition menu. To begin, select the partition, volume, or logical drive. Then, choose Delete from the Partition menu. A message will appear advising you that all data will be lost. Click Yes.

On an Intel-based system, Windows NT will not let you delete the volume with the system files, nor can you delete individual partitions that are part of a set without deleting the entire set. You can delete the system partition with the files needed to load Windows NT on a RISC-based system.

Saving and restoring configuration information
Before upgrading the operating system, you should be sure to save the disk configuration information. From the Partition menu, choose Configuration, and then click Save. A message will appear indicating that you need to insert a blank floppy disk, a floppy disk with a previous version of the configuration information, or the Emergency Repair Disk. Insert a blank floppy disk and then click OK. This procedure is used to save disk configuration information such as assigned drive letters, volume sets, stripe sets, stripe sets with parity, and mirror sets.

To restore disk configuration information, choose Configuration from the Partition menu, and then click Restore. A message warning that this operation will overwrite your current disk configuration information will appear. Insert the floppy disk—which may be the Emergency Repair Disk—containing the saved configuration information, then, click OK. At this point, you’ll have to restart your computer. This procedure is used for restoring the following disk-configuration information: assigned drive letters, volume sets, stripe sets, stripe sets with parity, and mirror sets.

Creating and extending a volume set
Keep in mind that MS-DOS cannot recognize volume sets. To create a volume set:
  1. Select two or more areas of free space from up to 32 different disks. Click on the first area of free space and then hold down the Ctrl key and click each of the other areas.
  2. From the Partition menu, select Create Volume Set.
  3. Disk Administrator will display the minimum and maximum sizes for the volume set. Type the size of the volume set you want to create, then click OK.

If you choose to use less than the total available space, Disk Administrator will use an equal percentage of the free space on each disk to create a partition of the size you specified. A single drive letter is assigned to the collection of partitions that make up the volume set.

To extend a volume set:
  1. Select an existing NTFS volume and then hold the Ctrl key while clicking one or more areas of free space. If you choose an area of space that is not NTFS, you’ll see an error message.
  2. From the Partition menu, choose Extend Volume Set.
  3. Disk Administrator will display the minimum and maximum sizes for the volume set. Type the size of the volume set you want to create and click OK.

Disk Administrator determines how much of the free space to use for the size you specified and then initiates a restart of your computer. Remember that a volume set cannot be part of a stripe set or mirror set.

Creating stripe sets
Each member partition of the stripe set must be on a different disk, up to a limit of 32 disks. Disk Administrator will also make all the partitions approximately the same size. Keep in mind that MS-DOS cannot recognize volume sets.

To create a stripe set, first select two or more areas of free space from up to 32 different disks. Click on the first area of free space, then hold down the Ctrl key and click each of the other areas. Choose Create Stripe Set from the Partition menu. Disk Administrator will display the minimum and maximum sizes for the stripe set. Type the size of the stripe set you want to create and click OK.

Disk Administrator will divide the total size by the number of disks to create equal-sized unformatted partitions in each of the selected disks. It will then assign a single drive letter to the collection of partitions that make up the stripe set. If you choose a number that cannot be divided equally, Disk Administrator will round to the closest higher or lower value.

To create a stripe set with parity, select three or more areas of free space from up to 32 different disks. Click on the first area of free space, then hold down the Ctrl key and click each of the other areas. From the Fault Tolerance menu, choose Create Stripe Set With Parity. Disk Administrator will display the minimum and maximum sizes for the stripe set with parity. Type the size of the stripe set you want to create, then click OK.

Disk Administrator will divide the total size of the disks selected by the number of disks to create equal-sized unformatted partitions in each of the selected disks. Then it will assign a single drive letter to the set. If you select a number that cannot be divided equally, Disk Administrator will round to the closest higher or lower value.

It takes more time to recover from the failure of a disk in a stripe set with parity than it does with a stripe set or mirror sets. If a member of a stripe set with parity fails, it becomes an orphan. You can regenerate the data for the orphaned member from the remaining members of the stripe set with parity.

To regenerate a stripe set with parity, do the following:
  1. Select the recoverable stripe set.
  2. Select an area of free space of equal or greater size.
  3. From the Fault Tolerance menu, choose Regenerate.
  4. Quit Disk Administrator and restart your computer.

When you restart the computer, the fault-tolerance driver reads the information from the stripes on the other member disks and re-creates the data of the missing member and writes it to the new member.

The regeneration process occurs in the background, and the stripe set with parity will not appear as healthy in the Disk Administrator status bar until regeneration is complete.

Creating and breaking mirror sets
To create mirror sets, select the partition you want to mirror by holding down the Ctrl key and clicking on an equal-sized or larger area of free space on another hard disk. Next, choose Establish Mirror from the Fault Tolerance menu. Disk Administrator will create an equal-sized partition in the free space for the mirror.

The same drive letter is used for both partitions of a mirror set. Any partition, even the system and boot partitions, can be mirrored onto another partition of equal or greater size on another disk, using either the same or a different controller.

Before you delete a mirror set, you should first break the mirror set to prevent data loss. Breaking a mirror set does not delete data, but you should still perform a backup first. You’ll then be ready to regain free space by deleting one or both of the partitions that made up the mirror set.

To break a mirror set, first select the mirror set that you want to break. From the Fault Tolerance menu, choose Break Mirror. Click Yes when a warning message appears. Then, click Commit Changes Now or quit and then restart Disk Administrator. Select one of the partitions that used to be part of the mirror set, and select Delete from the Partition menu. When the confirm message appears, click Yes.

Conclusion
Disk Administrator is a Windows NT tool that all system administrators should be familiar with. The easy-to-use graphical interface is quite an advance from Fdisk, the utility used for disk administration in the DOS world. In this article, I’ve examined the tasks Disk Administrator lets you perform.

Troy Thompson, MCSE+Internet, has worked in the automation field for 15 years, dealing with a variety of systems: Wang OIS, Unisys BTOS, UNIX, Windows 3.11, Novell NetWare, Windows NT 3.51, and Windows NT 4.0. He’s also worked as an administrator of a Novell and NT network, as well as a systems analyst for an IBM mainframe. Currently, Troy is the Information System Security Officer at the Information Management shop at Fort Knox. If you’d like to contact Troy, send him an e-mail.

The authors and editors have taken care in preparation of the content contained herein, but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for any damages. Always have a verified backup before making any changes.
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