How SnapVault backup of storage systems works
Backing up storage system qtrees using SnapVault involves starting the baseline transfers, making scheduled incremental transfers, and restoring data upon request.
How to start the baseline transfers:
- In response to command-line input, the SnapVault secondary storage system requests initial base transfers of qtrees specified for backup from a primary storage volume to a secondary storage volume. These transfers establish SnapVault relationships between the primary and secondary qtrees.
- Each primary storage system, when requested by the secondary storage system, transfers initial base images of specified primary qtrees to qtree locations on the secondary storage system.
How to make scheduled incremental transfers:
- Each primary storage system, in response to command line input, creates sets of scheduled SnapVault Snapshot copies of the volumes containing the qtrees to be backed up. For tracking purposes, you might name according to frequency, for example, “sv_hourly,” “sv_nightly,” and so on.
For each Snapshot set, SnapVault saves the number of primary storage Snapshot copies you specify and assigns each Snapshot a version number (0 for most current, 1 for second most recent, and so on).
- The SnapVault secondary storage system, in response to command line input, carries out a specified set of scheduled data transfer and Snapshot actions. For each of its secondary qtrees on a given volume, SnapVault retrieves, from the Snapshot data of each corresponding primary qtree, the incremental changes to the primary qtrees made since the last data transfer.
Then SnapVault creates a volume Snapshot copy of the changes in the secondary qtrees.
For each transfer and Snapshot set, SnapVault saves the number of secondary storage Snapshot copies that you specify and assigns each Snapshot copy a version number (0 for most current, 1 for second most recent, and so on).
Restoration upon request:
- If data needs to be restored to the primary storage system, SnapVault transfers the specified versions of the qtrees back to the primary storage system that requests them.
The following diagram illustrates SnapVault functionality.
Figure 1. SnapVault functionality
