System administrators have long since relied on Redundant Arrays of Inexpensive Disks (RAID) technologies to provide levels of fault tolerance for their server disk resources. And though the technology is a familiar mainstay in server management, its importance should not be overlooked. There are a couple of ways to leverage RAID to optimize disk management in Windows Server 2003. The first is creating RAID disks using disk controller configuration utilities, and the second is creating the RAID disks using dynamic disk configuration from within the Windows Server 2003 operating system. Hardware-based RAID SolutionsUsing two or more disks, different RAID-level arrays can be configured to provide fault tolerance that can withstand disk failures and still provide uninterrupted disk access. Hardware-based RAID is achieved when a separate RAID disk controller is used to configure and manage the disks participating in the RAID array. The RAID controller stores the information on the array configuration, including disk membership and status. Implementing hardware-level RAID configured and stored on the disk controller is preferred over the software-level RAID configurable within Windows Server 2003 Disk Management because the Disk Management and synchronization processes in hardware-level RAID are offloaded to the RAID controller. With Disk Management and synchronization processes offloaded from the RAID controller, the operating system will perform better overall. Another reason to provide hardware-level RAID as a best practice is that the configuration of the disks does not depend on the operating system. This gives administrators greater flexibility when it comes to recovering server systems and performing upgrades. Because there are many hardware-based RAID solutions available, it is important to refer to the manufacturer's documentation on creating RAID arrays to understand the particular functions and peculiarities of the RAID disk controller in use. Using Dynamic Disk RAID ConfigurationsWindows Server 2003 supports two types of disks: basic and dynamic. Basic disks are backward-compatible , meaning that basic partitions can be accessed by previous Microsoft operating systems such as MS-DOS and Windows 95 when formatted using FAT; and when formatted using NTFS, Windows NT, Windows 2000, and Windows .NET Server 2003 can access them. Dynamic disks are managed by the operating system and provide several configuration options, including software-based RAID sets and the capability to extend volumes across multiple disks. Though there are several configuration options, including spanned and stripped volumes, the only really fault tolerant dynamic disk configurations involve creating mirrored volumes (RAID 1) or RAID 5 volumes as described in the following list:
Using the Disk Management MMCMost disk- related administrative tasks can be performed using the Disk Management MMC snap-in. This tool is located in the Computer Management console, but the standalone snap-in can also be added in a separate Microsoft Management Console window. Disk Management is used to identify disks, define disk volumes, and format the volumes. New Feature in the Windows Server 2003 Disk Management Console A new feature in the Windows Server 2003 Disk Management console enables administrators to also manage disks on remote machines. To use the Disk Manager to create a software-based RAID, the disks that will participate in the array must first be converted to dynamic disks. This is a simple process by which the administrator right-clicks on each disk in question and chooses Convert to Dynamic, as shown in Figure 22.1. Figure 22.1. Convert basic disks to dynamic.
The system will require a reboot to complete if the system volume is being converted to Dynamic. After the disks are converted, perform the following steps to set up a Mirrored volume or RAID 1 of the system volume:
Using the Diskpart Command-Line UtilityDiskpart.exe is a flexible command-line disk management utility that performs most of the functions available to it with the Disk Management console. Using diskpart.exe, both basic volumes and dynamic volumes can be extended whereas the Disk Management can only extend dynamic volumes. The real value of using Diskpart.exe is that it can be run with a script to automate volume management. This is particularly useful when automating server builds across several servers that have the same characteristics. For more information on automatic server installations, refer to Chapter 11, "Implementing Windows Server 2003." Extend a Basic Volume Using Diskpart.Exe If you want to extend a basic volume using diskpart.exe, the unallocated disk space must be on the same disk as the original volume and must be contiguous with the volume you are extending. Otherwise, the command will fail. The syntax for Diskpart.exe is as follows : Diskpart.exe /s script The script referenced by the utility is a text file that will include the specific instructions necessary for the desired function. For example, to extend a volume using unallocated space on the same disk, the associated script file would look like this: Select Volume 2 Extend Exit |