Volume Filter Driver for Application-Consistent Backups
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Solution Overview
Problem
Conventional backup systems face inefficiencies in creating application-consistent backups, leading to resource drains on production and backup servers, network bandwidth issues, and difficulties in achieving granular recovery points in a timely manner, which negatively impact Recovery Point Objectives (RPO) and Recovery Time Objectives (RTO).
Innovation Solution
Implementing a volume filter driver to monitor changes on production server volumes, allowing for incremental data transfers to a backup server, creating application-consistent backups by freezing writes and using volume log files to track changes, and employing a Volume Shadow Copy Service (VSS) for snapshot management, enabling virtually continuous backups with reduced resource consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional backup systems create application-consistent backups by copying all data on production server volumes, then file state consistency is achieved, but system performance deteriorates and network bandwidth is wasted due to copying unchanged data
Solution Approach 1:
The patent extracts only the changed portions of data (incremental changes) from the production server volumes using a volume filter driver that monitors and identifies modifications. Instead of copying entire volumes, the system extracts and transfers only the specific data blocks that have changed since the last backup, thereby maintaining consistency while improving performance and reducing network bandwidth consumption.
Solution Approach 2:
The system performs preliminary actions by using a volume filter driver to continuously monitor and log changes to volume data before the actual backup process. The driver pre-identifies changed data blocks and prepares them for transfer, so that when a backup is initiated, only the necessary incremental changes are copied rather than scanning and copying entire volumes, thus improving system performance during backup operations.
2Loss of time
If conventional backup systems increase backup frequency to provide granular recovery points, then Recovery Point Objective (RPO) improves, but resource consumption on production and backup servers increases
Solution Approach 1:
The system extracts only the incremental changes that occurred since the last backup cycle using the volume filter driver's change monitoring capability. By transferring only these small incremental portions rather than complete volume copies, the resource consumption on both production and backup servers is significantly reduced, enabling more frequent backups to achieve better RPO without overloading server resources.
Solution Approach 2:
The patent applies partial action by performing backups at the incremental level rather than complete volume level. The volume filter driver identifies and backs up only the partial changed portions of data, which reduces the workload and resource consumption compared to full backups, thereby enabling more frequent backup operations to meet granular RPO requirements.
3Productivity
If application-specific backup mechanisms are used to backup only relevant data, then backup efficiency improves, but device complexity increases due to multiple application instances and APIs
Solution Approach 1:
The patent implements a universal volume filter driver that can monitor and track changes across multiple different applications and data types without requiring separate backup mechanisms for each. This single multi-functional driver replaces the need for multiple application-specific backup instances and APIs, thereby reducing system complexity while maintaining the efficiency of targeted data backup.
Solution Approach 2:
The volume filter driver acts as an intermediary component between the production server volumes and the backup system. It intercepts and monitors all data changes at the volume level, providing a unified interface for change detection and backup initiation. This intermediary approach simplifies the overall system architecture by eliminating the need for multiple application-specific backup agents and their associated complex API interactions.
4Reliability
If conventional backup systems transfer entire files even when only small portions are modified, then data consistency is maintained, but network bandwidth is wasted and transfer time increases
Solution Approach 1:
The system extracts and transfers only the specific changed portions of data (incremental changes) identified by the volume filter driver, rather than transferring entire files. The driver precisely identifies which data blocks have been modified, and only those specific portions are extracted and transferred to the backup server, reducing network bandwidth consumption and transfer time while maintaining data consistency through proper incremental backup management.
Data Source
AI summary
Data can be protected at a production server in a virtually continuous fashion, without necessarily imposing severe constraints on the source application(s). For example, a production server can create an application-consistent backup of one or more volumes, the backups corresponding to a first instance in time. A volume filter driver can monitor data changes in each volume using an in-memory bitmap, while a log file and/or update sequence number journal can keep track of which files have been added to or updated. The volume updates are also consistent for an instance (later) in time. At the next replication cycle, such as every few minutes (however configured), the volume filter driver passes each in-memory bitmap to the physical disk on the production server. The production server then sends the updates to the backup server, which thus stores application-consistent backups for the volume for multiple instances of time.