Point in time Snap Shotting
A full backup of a large data set can take a considerable time to complete. On multi-user systems there may be writes to that data while it is being backed up which introduces a version skew that may result in data corruption.
One approach to safely backing up live data is to temporarily disable write access to data during the backup.This is tolerable for low-availability systems.High-availability 24/7 systems, however, cannot bear service stoppages.
To avoid downtime, high-availability systems may instead perform the backup on a snapshot—a read-only copy of the data set frozen at a point in time—and allow applications to continue writing to their data.
There is some confusion caused by Vendors about the different types of snapshots available in the form of built in hardware-based, or third-party copy-related functionality. To confuse the matter further, these vendors often coin their own derivative name for the snapshot function.
To assist you in understanding how this technology works request an online workshop covering;
- Differences between hardware-based and software-based metadata snapshots
- Differences between image and snapshot
- Which Vendors snapshots do what
- How and where to use snapshot technology
- Using point-in-time copies
- Using Snapshots for Application protection in SQL Server/ MS Exchange/ SharePoint and Oracle
- Types of snapshot technologies
- Using snapshot for open files