Microsoft’s Windows Server 2003 has arrived. And the new operating system caters for the Storage Manager more than ever before. We take a look at some of the new and enhanced features Windows 2003 introduces and what likely benefits they will provide.
Volume Shadow Copy Service (New Feature)
I’m sure we can all think of occasions where we have inadvertently amended or deleted a crucial file. The pain experienced at losing important documents is only compounded when we discover the file is not on a backup – or may be a file created since the last backup was taken. Volume Shadow Copy (VSS) is a new feature aimed at reducing the “D’oh” factor out of accidental file deletions or modifications. VSS takes a point-in-time copy (or snapshot) of a disk volume (which at the moment is read-only). Copying occurs based on time or other triggered events, including system start-up and user logon. The shadow copy of the volume can then be accessed as a normal read-only directory, allowing files to be copied back into a location the user chooses. Enabling shadow copies requires at least 100MB of free space on the volume and each shadow copy further eats into the free space on the disk. VSS is not however, purely a file recovery tool. Through the use of “writers”, VSS can interact with applications to ensure shadow copies are taken consistently with the application. VSS also provides support for hardware-based volume copies. VSS information can also be accessed on the command line through the “vssadmin” command.
DISKPART Command (New Feature)
The new DISKPART command provides command line functionality to the features of the Logical Disk Manager (Disk Management in Computer Management). This means you can script the operations you’d normally have to perform via the GUI. It is possible to create volumes, convert basic disks to dynamic disks and most destructive of all, to delete disks and partitions. The command is a double-edged sword. Yes, it’s great to be able to create and destroy partitions with a single command, however on the negative side, there’s not a lot of confirmation enabled, so I was able to delete an entire partition (thankfully with only test data) before I’d realised what I’d done. I suggest that Microsoft needs to include confirmation by default and allow the user to bypass that confirmation using a switch on the command when running the command as part of a script.
Virtual Disk Service (New Feature)
VDS is Microsoft’s attempt to standardise the API infrastructure for managing storage from multiple vendors who currently implement their own API or command infrastructure. The Virtual Disk Service provides management API functions to existing tools such as Disk Management and the DISKPART command. In turn, VDS passes API calls to provider software, which interacts directly with the vendor hardware. The hardware vendor is expected to write the provider code. Microsoft has supplied providers for basic and dynamic disks in the standard distribution of Windows 2003 Server.
Automated System Recovery (New Feature)
ASR works in conjunction with the standard Windows Backup tool to create a snapshot of critical system files and configuration information that can be used to rebuild a crashed server. ASR is really a last resort tool, as it requires you to re-install a new copy of the operating system. The ASR configuration save information is written to a floppy disk during backup then re-used during the installation of the Operating System. You must also maintain a backup copy of your data, which also has to be restored after the Operating System is rebuilt.
Open File Backup (New Feature)
In previous versions of the “Backup” command, any open files didn’t get backed up. Through the use of VSS (Volume Shadow Copy Service), open files can now be backed up.
Encrypting File System (Enhanced Feature).
The Encrypting File System (EFS) was first introduced with Windows 2000. This encrypted the contents of an NTFS file or directory, preventing access to other than the encrypting user. EFS has been updated in Windows Server 2003 to allow access to be granted to more than one user. It is now also possible to encrypt offline files and files in web folders.
Chkdsk Command (Improved Feature)
Windows Server 2003 includes performance improvements to the “chkdsk” command. Microsoft quotes improvements of between 20% - 38% over Windows 2000 Server and 140% - 1200% over Windows NT 4.0 Server, however these figures are based on volumes containing millions of files.
DFS Enhancements (Improved Feature)
DFS (Distributed File System) allows data located on multiple servers to be accessed through a consistent Network share structure. In addition, data can be replicated between multiple servers to provide data resilience and failover capabilities. DFS has been enhanced in Windows 2003 Server to enable a single server to host multiple roots. Other improvements in DFS deliver more reliable load balancing, better file replication between DFS sites and servers, and closest-site selection for users accessing the network.
These are just some of the storage enhancements to Windows 2003 Server. Not discussed here are minor improvements to SAN support and the Multipath I/O driver development kit. Over the coming months, we hope to expand on the new storage features and develop some best practice recommendations for their implementation.