Fibre Channel Failover via Fabric Database Identity Swapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current storage systems face downtime issues when upgrading or replacing storage arrays, as data migration and reconfiguration require some downtime, disrupting critical applications.
Innovation Solution
The solution involves using a Fibre Channel fabric with a database that associates names and addresses of Fibre Channel ports, allowing data to be copied and port names/LUN names/numbers to be swapped between primary and secondary arrays, making the secondary array appear as the primary to hosts, thus enabling transparent failover and migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data migration and reconfiguration are performed to replace a storage array, then the storage system can be upgraded or replaced, but downtime occurs and host applications are interrupted
Solution Approach 1:
The patent implements preliminary data copying from the primary storage array to the secondary storage array before the failover event occurs. This advance preparation ensures that when failover is triggered, the secondary array already contains the necessary data and can immediately assume the primary array's identity through name and address swapping, eliminating downtime.
Solution Approach 2:
The patent introduces a fabric database as an intermediary that stores the mapping between Fibre Channel names/addresses and physical port addresses. During failover, the database is updated to redirect traffic from the primary array's name/address to the secondary array's physical address, providing a seamless transition without interrupting host applications.
2Ease of operation
If the secondary array assumes the primary array's identity through name replacement, then transparent failover is achieved, but the fabric database must be updated and reconfigured
Solution Approach 1:
The fabric database automatically updates itself when failover occurs. The system modifies the database entries to associate the primary array's name and address with the secondary array's physical port address, and this updated database is automatically distributed to all switches in the fabric, eliminating manual reconfiguration overhead.
3Reliability
If all data is copied to the secondary array before failover, then data integrity is maintained, but the copying process requires time and resources
Solution Approach 1:
The patent implements continuous or periodic data copying to the secondary array rather than copying all data at once before failover. This approach maintains data integrity by ensuring the secondary array has the necessary data while distributing the copying workload over time, reducing peak energy consumption and resource usage.
Data Source
AI summary
Failover is provided from a primary Fiber Channel device to a secondary Fiber Channel device. Source and secondary Fiber Channel devices are coupled to a Fiber Channel fabric having a database that associates Fiber Channel names and Fiber Channel addresses of Fiber Channel ports coupled to it. All data is copied from the primary Fiber Channel device to the secondary Fiber Channel device. In response to a failure, secondary port names and LUN names are replaced with the primary port names and LUN names, and the fabric updates its database so that the database associates the secondary port and LUN addresses with the primary port and LUN names. The secondary Fiber Channel device thereby assumes the primary Fiber Channel device's identity.