Virtual Tape Controller Bandwidth Adjustment for Disaster Recovery
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Solution Overview
Problem
In hierarchical computer storage systems, geographically separated virtual tape servers face challenges in optimizing data transmission rates, which can hinder disaster recovery capabilities due to high overhead, making it difficult for secondary sites to keep up with primary sites' processing and maintain real-time data backup.
Innovation Solution
The method involves adjustable aggregate bandwidth for virtual tape servers, where the system writes information to two geographically separated virtual tape servers using a virtual tape controller and channel extenders, setting throughput and age thresholds to dynamically adjust bandwidth based on actual throughput and queued file age to optimize data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is continuously backed up from primary site to secondary site, then disaster recovery capability is improved, but system overhead increases and secondary site cannot keep up with primary site processing
Solution Approach 1:
The patent dynamically adjusts the aggregate bandwidth of virtual host devices based on real-time system conditions. The virtual tape controller monitors the age of queued copy jobs and the actual throughput, then dynamically modifies bandwidth allocation to optimize both disaster recovery capability and transmission performance. This resolves the contradiction by making the system adaptive rather than static.
Solution Approach 2:
The system changes key operating parameters including aggregate bandwidth, throughput thresholds, and age thresholds to balance reliability and productivity. By adjusting these parameters based on system state, the patent achieves both continuous backup capability and sustained data transmission rates without one compromising the other.
2Productivity
If aggregate bandwidth of virtual host devices is increased, then data transmission rate is improved, but control overhead increases
Solution Approach 1:
The virtual tape controller implements feedback mechanisms by monitoring actual throughput and queued file age, then using this information to adjust aggregate bandwidth. This closed-loop control optimizes data transmission rates while avoiding excessive control overhead through intelligent, condition-based adjustments rather than continuous modification.
Solution Approach 2:
The system performs self-optimization by automatically adjusting its own bandwidth allocation based on monitored performance metrics. The virtual tape controller autonomously modifies aggregate bandwidth without requiring external intervention, reducing control overhead while maintaining optimal transmission rates.
Data Source
AI summary
A method to write information to two geographically separated virtual tape servers, where the method provides a file to a virtual tape controller, writes that file to a first virtual tape server, and queues a copy job for the file in the virtual tape controller. Subsequently, the method provides the file to a second virtual tape server. The method sets a throughput threshold, determines the actual VTC throughput, and determines if the actual VTC throughput exceeds the throughput threshold. The method sets an age threshold and determines if the copy job age is greater than that age threshold. If the actual VTC throughput is greater than the throughput threshold and the copy job age is greater than the age threshold, then the method decreases the first adjustable host bandwidth and/or the second adjustable host bandwidth, otherwise the method restores the bandwidth to a nominal value.