Utilizing External Disk Subsystems

Windows Server 2008 R2 is capable of utilizing and, in some cases, managing disks stored in external storage area networks (SANs) or disk subsystems. Many enterprise organizations, and actually many midsize organizations, deploy Windows systems connected to external disk storage. As organizations move toward consolidating and virtualizing servers, the need to provide fault-tolerant disk storage at the organization level instead of at the server level has become more common.

Hardware-Based Disk Arrays
As a best practice, whenever possible, use RAID-compatible disk controllers or SANs to provide fault-tolerant disk volumes to Windows Server 2008 R2 systems. Using externally managed RAID arrays will reduce server processing requirements and can also improve the recoverability of the system if operating system corruption is encountered.

Boot from Storage Area Networks
Many SAN vendors and Microsoft tout the ability to deploy diskless servers that boot from SAN disks. This configuration allows SAN vendors to completely manage the Windows system disks and can simplify the recovery or replacement of a server based on hardware failure or scheduled replacement.

Managing External Storage
Windows Server 2008 R2 provides a tool called “Storage Manager for SANs” to assist administrators in managing SAN-based disks. In most cases, however, SAN vendors provide and recommend the use of their own vendor-based management tools.

External Storage Support Requirements
Microsoft has very tight specifications when it comes to supporting external storage for Windows servers. Administrators who plan to utilize external storage should review the Windows Server 2008 R2 Hardware Compatibility List for external storage devices, storage controllers, driver types, driver versions, and controller firmware versions to verify supported compatibility before purchasing any external storage devices—that is, if the administrators want to be supported by Microsoft in the event of disk or data corruption.

Source of Information :  Sams - Windows Server 2008 R2 Unleashed (2010)