A software component that intercepts and processes I/O operations at the file system or device driver level, relevant to SQL Server backup tools that use Volume Shadow Copy Service (VSS) or Instant File Initialization.
- Filter drivers are used by backup software to intercept file system writes: They capture consistent point-in-time snapshots without quiescing the database.
- SQL Server backup solutions may use filter drivers to enable features such as: Block-level change tracking, instant virtualization of backups, or live mount capabilities.
- DBAs should be aware of filter drivers installed by backup software on SQL Server hosts: Improperly implemented filter drivers can cause I/O latency or system instability.
- Relevant Idera tools: SQL Safe Backup uses VSS-compatible techniques for reliable, consistent backup capture.
- Related terms: VSS, Backup, Instant File Initialization, Storage I/O.
