Disk Management

Dell OpenManage™ Array Manager 3.4

This chapter describes conceptual and procedural information about how Array Manager implements basic and dynamic disks. It also includes general disk functions.

Note There are particular considerations regarding dynamic disks and volumes on NetWare, Windows Server 2003, and Linux. See "Dynamic Disk and Volume Support on NetWare, Windows Server 2003, and Linux" for more information.

Basic and Dynamic Disk Overview

Physical disks can be either basic or a new type called dynamic. When you install the Microsoft® Windows NT® 4.0 or Windows® 2000 operating system, your hard disks are automatically initialized as basic. You can upgrade them to dynamic after the Array Manager installation is complete.

There are particular considerations regarding dynamic disks and volumes on NetWare, Windows Server 2003, and Linux. See "Dynamic Disk and Volume Support on NetWare, Windows Server 2003, and Linux" for more information.

Basic Disk Definition

Basic disks use the traditional disk partitioning mechanism used by MS-DOS®, Microsoft Windows 95® or Windows 98®, and Microsoft Windows NT operating systems. A basic disk can have up to either four primary partitions or three primary partitions plus an extended partition. This extended partition can be subdivided into a number of logical drives.

In Array Manager, a basic disk can also have "legacy" partitions and volumes if the disk was previously configured with Microsoft Windows NT Disk Administrator. These "legacy" volumes are different from volumes that you create with Array Manager. Array Manager does not allow you to change Disk Administrator volumes, but it lets you view and do limited management of them. See "Manage Volumes Created with Windows NT Disk Administrator" in the "Volume Management" chapter for more information.

You can create only primary and extended partitions on basic disks. You should create partitions on basic disks if you want computers running Microsoft Windows 98 or earlier, or MS-DOS to access these partitions.

Dynamic Disk Definition

A dynamic disk is a physical disk that can contain dynamic volumes created with Volume Manager. A dynamic volume organizes space on one or more physical disks by using a specific type of volume layout. The five types of dynamic volumes are simple, spanned, mirrored, striped, and RAID-5.

On a dynamic disk, space is organized through volumes rather than partitions. Because a dynamic disk does not have the partitioning scheme used by Windows 95/98 and MS-DOS, you cannot access dynamic disks through those operating systems.

For more information on the dynamic volume types, see the "Dynamic Volume Types" in the "Volume Management" chapter.

Working with Basic Disks

This section's topics are:

Basic Disk Functions

Array Manager allows you to do the following on basic disks:

Create and delete primary and extended partitions.
Create and delete logical drives within an extended partition.
Format a primary partition and mark it as active.
View volumes created by NT Disk Administrator. These include simple partitions, simple and spanned volumes (volume sets), striped volumes (stripe sets), mirrored volumes (mirror sets), and RAID-5 volumes (stripe sets with parity).
Check disk properties such as capacity, unallocated space, and current status.
Make drive-letter assignments for basic volumes, partitions, CD-ROMs, DVDs, and other removable devices.
Upgrade a basic disk to dynamic if the basic disk is empty.

Basic Disk Limitations

You cannot perform the following tasks on a basic disk:

Create or change volumes created in NT Disk Administrator.
Extend basic volumes.

Create Primary and Extended Partitions

Use the Create Volume wizard to create primary partitions and extended partitions on a basic disk.

From the Task menu, select Create Volume. You can also select a basic disk, right-click to display the context menu, and select Create Volume. Both methods display the Create Volume wizard window.
The Create Volume wizard's first page displays information about volumes. Read the information and then click Next to continue.
You are asked to select whether to create a partition or a volume. If you have started with a basic disk, the Partition radio button is already selected. The group that the partition will be created in is displayed. Click Next to continue.

Select Partition Type

The Create Volume wizard asks you to select a partition type (primary or extended) and the size of the partition. Click Next to continue.

Note If the disk already has either four primary partitions or three primary partitions and one extended partition, Array Manager displays a message that you have exceeded the number of partitions and will not let you create any more. Click OK and return to the Array Manager console.

Select Disks and Region

Select a disk and free space on which to create the partition. The dialog box shows a list of available disks and free spaces. Check the box for the disk and free space you want to use, and click to Next continue.
If there is no free space on the selected disk, the free space selection is shaded. A message appears on the wizard that indicates a lack of available disk space. Click Next to continue.

Assign a Drive Letter or Drive Path

Assign a drive letter to this volume if you want to format the partition. (Or you can assign a drive letter afterward.) If you are using a Windows 2000 machine, you can also mount the partition at an empty NTFS folder. Click Next to continue.

Format

Select the Format this volume check box if you want to format the partition. Array Manager allows you to format using either FAT or NTFS. In addition, for Windows 2000 only, you can use FAT32.
- FAT (File Allocation Table) — A file system used by MS-DOS, Windows 3.x, and Windows 95/98. Microsoft Windows NT and Windows 2000 also can use the FAT file system. The operating system maintains a table to keep track of the status of various segments of disk space used for file storage.
- NTFS (NT File System) — An advanced file system designed for use specifically within the Microsoft Windows NT and Windows 2000 operating systems. Use this format if you want to use file and folder compression. Note that NTFS cannot be used by MS-DOS, Windows 3.x, or Windows 95/98.
- FAT32 — (Windows 2000 only) A derivative of the file allocation table (FAT) file system. FAT32 supports smaller cluster sizes than FAT, thus providing more efficient space allocation on FAT32 drives. FAT32 is designed for larger disks than FAT.
To name the partition, type a name in Volume Label. If you do not enter a name, your partition will be named "New Volume" by default.
Select an allocation unit size, if you choose to use a size other than the default. Default settings are strongly recommended for general use.
If desired, select a formatting option:
- Quick format — Use this method to skip scanning for bad sectors in the partition during formatting.
- Enable file and folder compression — Use this method to compress the folders and files that are added to the volume. This option is available only if the partition is being formatted with NTFS.
Click Next to continue, then Finish.

Create Logical Drives in an Extended Partition

An extended partition can be subdivided into as many as 32 logical drives. You can use all or part of the free space in an extended partition when creating logical drives. An extended partition or a logical drive cannot span multiple disks.

Select an extended partition from the left panel tree view.
Click Create Logical Drive to display the Create Volume wizard. Click Next to move through the wizard's Select Partition or Volume window. (Partition is selected by default.)

Select Partition Type

At the Select Partition Type window, the Logical Drive button is automatically selected, and displays the largest logical drive size that can be created on that drive.
Type the size of the logical drive that you want to create, and then click OK.

Select Disks and Region

Select the disk and free space for the partition.

Assign Drive Letter

Choose a drive letter if you want to name and format the logical drive. If you do not choose a drive letter, the logical drive cannot be formatted. (A drive letter can be assigned later.)
Click Next to continue, then Finish.

The Status column in list view displays Formatting and displays the percentage of completion of the format process. The logical drive status changes to Healthy when formatting is complete, and the logical drive becomes available for use.

Dealing with Removable Media

In the graphical view, removable-media devices are labeled Removable. They are considered basic disks.

You can create only one primary partition on removable-media devices. You cannot create extended partitions, logical drives, or dynamic volumes on removable-media devices. You cannot upgrade removable-media devices to dynamic volumes. Removable-media devices can contain only one primary partition and can be formatted with FAT or NTFS. You cannot mark a primary partition on a removable-media device as active.

Upgrading a Basic Disk to Dynamic

On Windows NT, a basic disk can be upgraded to dynamic only if it does not contain partitions, logical drives, or basic volumes.

On Windows 2000, Array Manager can upgrade a basic disk that contains partitions, logical drives, or Disk Administrator volumes. Array Manager converts the partitions and logical drives to simple dynamic volumes and the Disk Administrator volumes to dynamic volumes of the appropriate corresponding RAID type. This capability is called encapsulation and is described in more detail in "Upgrade Disks with Legacy Volumes to Dynamic" in the next chapter, "Volume Management."

After you upgrade a basic disk to a dynamic disk, you cannot change the dynamic volumes back to partitions or basic volumes. A dynamic disk cannot contain partitions or logical drives, nor can it be accessed by the MS-DOS or Windows 95/98 operating systems.

To Upgrade a Basic Disk to a Dynamic Disk

Right-click the disk you wish to upgrade and select Upgrade Dynamic Disk from the context menu that appears.
The Upgrade Disk wizard explains information about upgrading. Click Next to continue.
You are asked to select disks to upgrade. Add the basic disks you want to upgrade to the list of dynamic disks and click Next to continue, then Finish.

Working with Dynamic Disks

This section's topics are:

Dynamic Disk Advantages

When you upgrade a dynamic disk, Array Manager writes a small database onto the upgraded disk to store volume management information about the disk and all other dynamic disks present on your system. This database is what gives a dynamic disk many advantages:

Users can create dynamic volumes without restarting the system.
Volumes can be accessed continuously, even across disk reconfiguration events.
Simple volumes and spanned volumes can be readily extended without the need to find contiguous space on the available disks. These volumes can also be extended in size without rebooting the server. This is known as Online Volume Expansion (OLVE).
Disk configuration information is contained on the disk, not in the registry. The disk configuration information is also replicated across all dynamic disks so that the failure of one disk will not obstruct access to data on other disks.
Dynamic disks can be mirrored, spanned, or striped across disks.
Dynamic disks provide volume migration, which is the ability to move a disk from one Microsoft Windows NT/2000 system to another system without loss of data.

Dynamic Disk Limitations

Dynamic disks cannot be accessed by MS-DOS or Microsoft Windows 95/98. The Microsoft Windows NT and Windows 2000 operating systems can access dynamic disks, but the dynamic volumes on dynamic disks cannot be changed without Array Manager.

Virtual disks of Fibre Channel storage in a Storage Area Network (SAN) can be converted to dynamic disks, but this should be done with the following considerations:

Dynamic disks of SAN storage must not be moved by way of Dell OpenManage Storage Consolidation from server to server. Once a virtual disk of SAN storage is made dynamic, it must remain assigned to the server.
It is better to upgrade virtual disks of SAN storage to dynamic only on an as-needed basis. This will make it easier to choose dynamic disks when creating dynamic volumes.

Creating Volumes on a Dynamic Disk

You can create dynamic volumes on dynamic disks only. To create and delete simple, spanned, striped, mirrored, and RAID-5 volumes, see "Creating a Dynamic Volume" in the "Volume Management" chapter.

Extending a Simple or Spanned Volume on a Dynamic Disk

You can extend simple and spanned volumes without having to locate unallocated contiguous space on the disk. See "Extending a Dynamic Simple or Spanned Volume" in the "Volume Management" chapter.

Reactivating Dynamic Disks

A dynamic disk may appear as a missing disk when it is corrupted, powered down, or disconnected. You can reactivate a dynamic disk to bring it back online.

To Reactivate a Missing or Offline Disk

Right-click the disk marked Missing or Offline dynamic disk.
Select Reactivate Disk from the context menu. The disk should be marked Online after the disk is reactivated.

Merging a Foreign Disk

Dynamic disks with a Foreign status are disks that have been moved from another computer. You cannot reactivate a foreign disk. To change a foreign disk's status and enable it to be seen as a part of the current computer system, you will need to use the command Merge Foreign Disk. For details on how this command is done, see the next topic "Moving a Dynamic Disk to Another Computer."

Moving a Dynamic Disk to Another Computer

Before you disconnect the disks, make sure the status of the volumes on the disks is Healthy. If the status is not Healthy, you should repair the volumes before you move the disks. You need to prepare disks for removal in some cases. See "Prepare to Remove" in the "PERC Subsystem 1 Controllers: PERC 2/SC, 2/DC, 3/SC, 3/DCL, 3/DC, 3/QC, 4/SC, 4/DC, 4/Di, 4/IM, and CERC ATA100/4ch" chapter. It is also recommended that you back up all data on your volumes before you move disks to another computer.

Note The ability to move dynamic disks to another computer is not supported with SAN storage. Only basic disks can be moved between servers on a SAN. Refer to the Dell OpenManage™ Storage Consolidation software documentation for more information. In addition, dynamic disks and dynamic volumes are only supported on Windows NT and Windows 2000 operating systems.

To Move a Dynamic Disk to Another Computer

Turn the computer off, remove the physical disks, and then install the physical disks on the other computer. Restart the computer.
Open Array Manager.
In most cases, the disks are merged automatically. However, if the disks appear in the disk list and graphical views as Foreign, right-click a new disk, click Merge Foreign Disks, and then follow the instructions on your screen.

Notes

After you merge a dynamic disk from another computer, you can see and use any existing volumes on that disk.
Every time you remove disks from or merge disks to a computer, you must click Rescan Disks and then verify that the disk information is correct.
You can move multiple disks from different machines to another computer by installing the disks, opening Array Manager, right-clicking any of the new disks, and then clicking Merge Foreign Disks. The disks are grouped according to the computer name they were moved from. You can choose which disks from the group you want to add by clicking Select Disk. However, if you do not have any dynamic disks installed, then all of the disks are added regardless of the disks you selected.
After you have merged the disk or disks, another dialog box appears that lists the conditions of the volumes. Review this information carefully.

Reverting a Dynamic Disk to Basic

You can revert a dynamic disk to basic if there are no volumes on the disk. If volumes exist, you must delete them before you can revert the disk. Disks shown in Array Manager to be unreadable or to be Foreign disks can be reverted, but doing so causes you to lose all existing data on the reverted disk.

General Disk Functions

This section on general disk functions has the following topics:

Add a New Disk to Your System

Install or attach the new physical disk (or disks).
Click View, and then click Rescan, or select Rescan from the toolbar.

Array Manager should detect the new disk after you click Rescan. However, if Array Manager does not detect the new disk, you may need to restart your computer.

New disks are added to the computer as basic disks. On Windows NT 4.0, you can upgrade a new disk to dynamic as long as the basic disk is empty. It cannot contain volumes or partitions. On Windows 2000, you can update basic disks that contain data to dynamic. See the section "Upgrade Disks with Legacy Volumes to Dynamic" in the "Volume Management" chapter.

Update Disk Information Using Rescan

When Array Manager rescans disks, it scans all attached disks for disk configuration changes. It also updates information on removable media, CD-ROM drives, basic volumes, file systems, and drive letters.

Every time you remove or add disks to a computer, you must click Rescan and then verify that the disk information is correct.

To Rescan Disks

From the View pull-down menu, select Rescan, or select the Rescan icon from the toolbar.

A rescan can take several minutes, depending on the number of devices installed.

Refresh the Array Manager Console Display

Use this option to refresh drive letter, file system, volume, and removable-media information. Refresh also checks to see whether unreadable volumes are now readable. However, it does not scan hardware. To update hardware information, use Rescan instead.

From the View pull-down menu, select Refresh, or select Refresh from the toolbar. The General tab view displays a percentage status line under the Progress column in the right pane.
After the operation is finished, the Array Manager console displays current information.

Write a Disk Signature

Windows requires that a disk have a signature on it before it can be used. Most controllers require that the write signature be added manually. The PERC 2, PERC 2/Si, PERC 3/Si, and PERC 3/Di controllers on Windows NT are the only exceptions.

When you create a virtual disk and then do a rescan, the newly created virtual disk appears under the Disks storage object. If the disk needs a signature to be written manually, its icon will display an error symbol. Also, its type will be listed as "No Disk Signature" in the disks displayed in the right pane of the console. If left unsigned, the disk cannot be used.

Use the following steps to write a disk signature. This procedure assumes that you have already created the virtual disk.

Expand the Disks object in the Array Manager tree view.
Right-click a virtual disk that needs a write signature to display the Write Disk Signature dialog. This dialog displays all virtual disks that require a disk signature.
Select the virtual disks for which you wish to do a write signature. You can do a write signature on more than one virtual disk at the same time.
Click Ok.

Once a signature is written on a disk, the disk is displayed as a basic disk. You can create partitions on the basic disk, or you can upgrade the disk to dynamic to create volumes on it.

Monitoring Disk Reliability

Array Manager supports Self Monitoring Analysis and Reporting Technology (S.M.A.R.T.) on array disks that are S.M.A.R.T. enabled.

S.M.A.R.T. performs predictive failure analysis on each disk and sends alerts if a disk failure is predicted. The RAID controllers check array disks for failure predictions and, if found, pass this information to the Array Manager console. Array Manager immediately displays an alert icon on the disk. Array Manager also raises an alert under the Events tab and in the Windows Event Log.

Note When a controller's I/O is paused, you will not receive S.M.A.R.T. events.

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