Transparent Storage Array Data Migration Without Downtime
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Solution Overview
Problem
Current storage systems require downtime for upgrading or replacing storage arrays, as data and connections need to be migrated and re-initialized, disrupting access to critical information and applications.
Innovation Solution
A method for transparently migrating data and management information between storage arrays, allowing the array management interfaces to be exchanged during a data migration event, ensuring continuous access and operation without modifying existing management applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data and connections are migrated from source storage array to destination storage array, then storage array can be upgraded or replaced, but downtime occurs and host applications lose access to storage array
Solution Approach 1:
The patent applies preliminary action by copying all data from the source storage array to the destination storage array before the actual migration event. This pre-copying ensures that when the migration is triggered, data is already available at the destination, eliminating downtime. The system performs the data duplication in advance during normal operation, so the switchover can happen instantly without affecting host application access.
Solution Approach 2:
The patent uses an intermediary approach by introducing a migration management system that coordinates between source and destination arrays. This intermediary manages the array management interface exchange and controls the migration process, allowing seamless switching between arrays without host awareness. The intermediary ensures continuous availability by managing the transition transparently.
2Adaptability or versatility
If storage array is upgraded or replaced, then storage system functionality is improved, but re-initialization and reconfiguration are required
Solution Approach 1:
The patent applies copying by creating a complete replica of the source array's data and management interface at the destination array. The destination array copies not only data but also the array management interface, allowing hosts to continue accessing storage through the same interface without reconfiguration. This copying approach preserves the original system configuration while enabling hardware upgrades.
Solution Approach 2:
The patent inverts the traditional migration approach by having the destination array assume the source array's identity and interface rather than requiring hosts to adapt to new interfaces. Instead of reconfiguring hosts to point to new arrays, the system makes the new array present itself as the original array through interface exchange, reversing the usual adaptation direction.
3Productivity
If data migration is performed transparently, then host applications continue uninterrupted access, but management information must be exchanged between arrays
Solution Approach 1:
The patent merges the source and destination array management interfaces by exchanging them during migration. The destination array adopts the source array's management interface characteristics, combining the new hardware with the old interface identity. This merging allows transparent migration because the management interface remains consistent while the underlying hardware changes.
Data Source
AI summary
Described are systems and methods of migrating data from a source array to a destination array transparently with respect to a management application program executing on a host system and using management information to send management messages to the storage arrays. Data are copied from the source array to the destination array during a data migration event. A first array management interface is associated with the source array and a second array management interface is associated with the destination array. Each array management interface includes management information that a management application executing on the host can use to communicate with the storage array. The first and second array management interfaces are exchanged during the data migration event so that the array management interface associated with the destination array becomes associated with the source array and the array management interface associated with the source array becomes associated with the destination array.