The following is tip #10 from "10 tips in 10 minutes on backup and restore technologies," excerpted from Chapter 5 in Dilip C. Naik's book, Inside Windows Storage, published by Addison-Wesley/Prentice Hall.
Backup operations have evolved in terms of both user requirements and the technology used to accomplish backups. Usage requirements have dictated that backups be made more frequently, yet without disrupting application access to data. Backup operations evolved from stand-alone backups to backup operations happening across a LAN to backup operations happening in a SAN environment. One problem that backup applications need to solve is backing up open files being accessed by active programs while the backup is being done.
In addition, backup applications have had to deal with a multitude of APIs that are specific to an application version and specific to an operating system version. Yet another trend has been to create the initial backup from disk to disk, via a snapshot operation. Backup to tape is increasingly becoming a secondary backup operation, from the snapshot volume to tape.
The Windows volume shadow copy service provides an efficient way to create snapshots. The architecture provides for all important components, including major applications such as databases and messaging servers to participate in the snapshot creation. Microsoft provides only the infrastructure to create a snapshot. Software vendors may use this infrastructure to build an application that can create and manage multiple snapshots.
Once a snapshot has been created, a backup may be created from the snapshot. Standard protocols such as NDMP may be used to accomplish the backup operation.
10 tips in 10 minutes on backup and restore technologies
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: Windows XP and Windows Server 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.