New Features in Windows Server 2003
The most significant difference between storage alternatives in Windows Server 2003 compared to its predecessors is the support for Itanium machines with their GUID-based partitioning system. There are also several feature enhancements that simplify IA32 operation. One of these enhancements, however, relinquishes a bit of backward compatibility. Here are the new features:
In Windows 2000, it was necessary to convert a basic disk to a dynamic disk to add more space to an existing volume. In Windows Server 2003, Basic disk partitions can be extended. This is true even for the system partition.
Improved Dynamic disk upgrades.
The Master Boot Record is modified during dynamic disk conversion to remove all but the necessary partition table entries. This eliminates arbitrary restrictions on dynamic volume operations.
A new utility, Diskpart, makes it possible to do all disk management from the command line. This feature has been a long time coming. With it, you can script an entire installation of Windows Server 2003 including the creation of additional partitions.
Dropped support for classic fault tolerant (FT) disk sets.
Here's some good news/bad news. The good news is that the underlying LDM code was modified extensively to improve performance. In benchmarks involving disk I/O, Windows Server 2003 handily outperforms Windows 2000, which itself outperformed Windows 9x. The bad news is that these changes relinquished backward compatibility with classic NT4 fault tolerant disk sets.
The last point bears further discussion. Under Windows 2000, you could upgrade a server with fault tolerant Ftdisk disk sets as long as one of them wasn't a mirror of the system partition. You would then convert the Ftdisk set to a dynamic volume after converting the disks to dynamic disks.
Under Windows Server 2003, if you have classic NT Ftdisk striped or volume sets, you must remove them prior to upgrading. To remove the Ftdisk set, you must back up and delete the FTdisk set, do the upgrade, then convert the disks to dynamic disks and configure the volume, then recover your data from tape.
If you use Ftdisk sets to mirror the operating system drive on a classic NT machine, you must break the mirror, do the upgrade, then make the disks into dynamic disks and recreate the mirror.
If you attempt to upgrade a system with Ftdisk sets, you will get an error message right at the start of Setup. The error is a little misleading, because it refers to NT4 basic disks when it should say NT4 fault tolerant disks. If the operating system is mirrored, the error is critical and you cannot upgrade. If data disks are mirrored, striped, or have volume spans, the error is simply a warning. If you go ahead and upgrade, though, you'll notice that the Ftdisk drive set appears in the Disk Management console with a drive letter, but it is inaccessible.
There is a workaround if you neglected to back up the data in the Ftdisk set prior to upgrading. The Support Tools on the Windows Server 2003 CD contains a utility called FTONLINE that you can use to mount the Ftdisk set in read-only mode so you can recover the data.