With Windows Server 2003, Microsoft created new levels of service availability and capability for all sizes of companies. In my opinion, Microsoft has finally started looking at disaster recovery in earnest.
Perhaps the most important of the new features dealing with disaster and recovery is the Volume Shadow Copy Service (VSS), which is available in all versions of WS2K3.
With VSS, you can set up point-in-time copies of data from specific volumes, and then restore data from any of the point-in-time copies you create when you perform a restore. The two major advantages touted by Microsoft are the ability for clients to restore accidentally deleted data without involving IT staff and the ability to create more efficient backup strategies.
For IT support pros, the number one request is usually to restore data lost due to human error. Users inadvertently save a file with bad information, they delete a file by accident, or something else goes wrong with a file.
When users need to retrieve this data, it often requires the support pro to pull out backup tapes and perform manual restores. It's time-consuming, and it keeps IT staff from performing other IT duties.
VSS allows administrators to declare shared folders on servers for point-in-time copies at regular intervals (to a max of 65 copies held at any given time). This allows end users to safely play around in the files and still retrieve earlier versions at will, without intervention from the IT department.
Issues to consider
The only drawback is that you may need more disk space for each shadowed volume, as you must store those point-in-time copies somewhere. However, since VSS employs a form of pointer data, the copies take up less space than you would expect, and you can store several copies effectively and efficiently.
You can also use backup and replication tools designed to work with VSS to move the copies to another VSS-capable server in another site. So, if the original server is lost in a disaster, your end users can still access their data. Since VSS takes snapshots at intervals and doesn't lock them when parent files are in use, open file locks don't affect the replication and backup tools.
In addition to replicating open files, you can also back up VSS snapshots while end users are working on the files you're trying to protect. This feature greatly enhances backups by eliminating backup windows, open file locks, and other hindrances.
You'll still encounter CPU utilisation issues from running backup agents and LAN utilisation issues from backup data going across the network, but it's generally not enough to prevent end users from using files.
Backing up the VSS snapshots produces clean images of the data as well as the ability to restore point-in-time copies. You can either restore the entire snapshot and pull out what you need, or you can use a VSS-enabled backup tool and restore individual files and folders.
Since you're backing up point-in-time copies of files, you can easily use a replication tool to move the VSS snapshots in real time to another server in your disaster recovery site and perform the backup there, creating off-site backups by default. Companies required to keep backups in an off-site location will find this a great boon for making DR systems and backup systems work smoothly together.
With a combination of good planning and newer backup and replication technologies, the Volume Shadow Copy Service will help enhance your disaster recovery plan. VSS even gives smaller shops the ability to restore lost data at a level that has long been the domain of the enterprise arena. Meanwhile, VSS offers larger companies even more recovery options than standard tools and provides the ability to free up IT professionals from some common data recovery tasks.
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