You store and retrieve data from a hard disk drive. Windows Sever 2003 supports different types of disks, such as basic disks and dynamic disks. A basic disk is accessible by previous versions of Microsoft operating systems, such as, MS-DOS and Windows 98. The disk space in a basic disk is allocated into partitions. The space in a dynamic disk is allocated into volumes. A basic disk can have up to four partitions on a single disk where as a dynamic disk can have any number of volumes.
1.Physical Disk
2.Logical Volume
3.Mounted Volume
4.Fault Tolerance
5.Basic Disk
6.Dynamic Disk
1. Physical Disk
A physical disk is a storage medium supported by Windows Server 2003. The physical disk is the actual disk that you install on the server Windows Server 2003 detects all hard disk drives as basic disks. You can covert a basic disc to a dynamic disk. It also enables you to create partitions and volumes.
2. Logical Volume
Logical volume is the basic storage unit that you can configure. It is the space on a disk, which the system recognizes as a file system. It can include space from more than one disk. The same drive letter represents the logical volumes on a disk.
3. Mounted Volume
Windows Server 2003 supports the NTFS file system. In NTFS, file system you can skip the process of assigning a drive letter to the volume. You can also mount a volume into a folder using the NTFS file system. For example, you create a new folder, Test, in a volume and assign a drive letter to it, for example, T. You can mount an existing volume, for example, Z to the folder. When you navigate to the folder Test under the volume T, you can access the contents of the volume Z.
4. Fault Tolerance
Fault tolerance represents the capability of the disk to retain information in the case of a power failure. The fault tolerance configuration for a disk utilizes two or more hard disk drives. The disk space is allocated among the disk drives to store data so that the system can recover data in case of a single drive failure. Windows Server 2003 does not support fault tolerance if two or more disks fail at the same time.
5. Basic Disk
The basic disk is the most common disk storage. The disk space is divided into partitions. The Master Boot Record of the drive stores the partition information, such as, partition size and partition location. A basic disk can contain up to four partitions.
6. Dynamic Disk
In a dynamic disk, the space is divided into volumes. A dynamic disk supports unlimited number of volumes. The Logical Disk Manager service controls the volumes and stores the volume information in a database. Windows Server 2003 supports five types of volumes that you can create and configure in a dynamic disk. They are:
Simple Volume - Indicates the volume type created on a single dynamic disk. A simple volume cannot extend to more than one disk. This volume type is used on a drive that has a lot of space to contain a single volume. Therefore, this volume type is treated as a hard disk with only one partition. You can create a simple volume on a FAT, FAT32, and NTFS file system.
Spanned Volume - Combines the disk space of two or more dynamic disks in a volume. A spanned volume can combine the space of 32 dynamic disks in a volume. In a spanned volume, the data is written sequentially. Sequential writing indicates that the system uses the disks one after another to write data. A spanned volume does not support fault tolerance. You cannot access data in the entire volume if any one of the disks in a spanned volume crashes.
Striped Volume - Divides data into blocks called stripes. The striped volume stores data simultaneously on two or more disks. The combined disks in a striped volume are called a striped set. A striped volume also does not support fault tolerance. You cannot access data from a striped volume if one of the disks fails.
Mirrored Volume - Creates a copy of a simple volume on independent disks. A mirrored volume is also called as Redundant Array of Inexpensive Disks-i. A mirrored volume contains a primary and secondary drive. The data on the primary drive is monitored and copied on to the secondary drive.
Redundant Array of Inexpensive Disks (RAID) Volume - Stores data in equal stripes across an array of three or more disks. A Redundant Array of Inexpensive Disks volume is fault tolerant. In the event of a disk failure, you can recover the data.
