Veritas NetBackup™ Snapshot Client Administrator's Guide
- Introduction
- Snapshot Client features
- About snapshot basics
- Off-host backup overview
- Off-host backup methods
- Snapshot Client requirements
- Installation
- Policy configuration
- Selecting the snapshot method
- Configuration parameters for Snapshot Client
- About using alternate client backup
- Configuring alternate client backup
- Policy configuration tips
- About disabling snapshots
- FlashBackup configuration
- Instant Recovery configuration
- About Instant Recovery
- About sizing the cache for Instant Recovery copy-on-write snapshots
- About configuring VxVM
- About storage lifecycle policies for snapshots
- Network Attached Storage (NAS) snapshot configuration
- Configuration of software-based snapshot methods
- Support for Cluster Volume Manager Environments (CVM)
- Configuration of snapshot methods for disk arrays
- About the new disk array snapshot methods
- Disk array configuration tasks
- OS-specific configuration tasks
- About VSS configuration (Windows)
- About EMC CLARiiON arrays
- Configuring NetBackup to access the CLARiiON array
- Configuring a NetBackup policy for a CLARiiON array method
- About EMC Symmetrix arrays
- About configuration for EMC_TimeFinder_Mirror
- About configuration for EMC_TimeFinder_Clone
- About HP EVA arrays
- Verifying connectivity from clients to array using SSSU 5.0
- About IBM DS6000 and DS8000 arrays
- Configuring NetBackup to access the IBM DS6000 or DS8000 array
- About IBM DS4000 array
- About Hitachi SMS/WMS/AMS, USP/NSC, USP-V/VM
- Hitachi array software requirements
- About HP-XP arrays
- About array troubleshooting
- Notes on Media Server and Third-Party Copy methods
- Backup and restore procedures
- About restores from a FlashBackup backup
- Instant Recovery restore features
- About configurations for restore
- About restoring from a disk snapshot
- Troubleshooting
- Logging directories for UNIX platforms
- Logging folders for Windows platforms
- FlashBackup and status code 13
- Appendix A. Managing nbu_snap (Solaris)
- Appendix B. Overview of snapshot operations
- Appendix C. NetBackup integration with CloudPoint for snapshot managment
About snapshot rotation
NetBackup Snapshot Client implements a rotation scheme for managing snapshot resources for some snapshot methods.
In the following bulleted example, the system is configured to have three snapshots available for instant restore ("undo") at any time:
The state of the client's backup selection list is captured in the first Instant Recovery snapshot, and the snapshot is retained. In other words, it is not deleted, even if the backup image is also copied to a storage unit.
When the backup policy runs again, recent changes in the client's backup selection list are captured in a second snapshot. This snapshot is created on a second device that was allocated for this purpose. The first snapshot is retained, in case a restore is needed from that data.
When the backup policy runs a third time, a third snapshot is created on the third allocated device. At this point three snapshots representing three different states of the client data are available for restore.
When the policy runs a fourth time, no additional snapshot device is available: one of the existing devices must be reused. The system "rotates" the devices, overwriting the first snapshot with the fourth (most recent) one. Although the earliest snapshot is now gone, the three most recent snapshots are available for restore.
In this figure, the next Instant Recovery backup overwrites the snapshot that was made at 12:00 noon.
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