Backup is performed for various reasons, and those reasons very often dictate the investment made in accomplishing the backup. The assurance of data availability is the primary reason for creating backups. The higher the data availability requirements, the more investment needs to be made. For example, one form of backup that runs continuously is disk mirroring, in which every data write operation is reflected to another disk to guarantee extremely high data availability.
Data archival also is used to meet legal and other needs in which the data does not have to be accessible immediately but can be produced on demand in a reasonable amount of time, measured in hours, days, or weeks.
Backups are sometimes used to transport data—for example, when one decides to create another data center at a distant geographical location. A similar motivation is to migrate the data to new hardware or, more rarely, a different server platform.

WINDOWS BACKUP AND RESTORE TECHNOLOGIES

Introduction
Tip #1: Reasons for backup and restore
Tip #2: Backup problems
Tip #3: Backup classifications
Tip #4: Windows 2000 backup utility
Tip #5: Techniques to create a volume snapshot
Tip #6: XP and Windows 2003 volume shadow copy service
Tip #7: Windows-powered NAS devices and snapshots
Tip #8: Network Data Management Protocol
Tip #9: Practical implications
Tip #10: Summary
About the author: Dilip C. Naik has more than twelve years of experience in various roles at Microsoft, including software engineer, program manager, and technical evangelist. His contributions include writing CIFS/SMB code, CIFS-related RFCs, code and documentation for the Windows NT Installable File System Kit, as well as Windows Management Instrumentation (WMI) and performance/management (including storage management) features for the Windows platform. Dilip has also represented Microsoft on a number of industry standards organizations.