Storage Array Migration Without Downtime
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current storage systems face downtime issues during array upgrades or replacements, as data migration from one storage array to another requires re-initialization and reconfiguration, disrupting access to critical information and applications.
Innovation Solution
A method for transparent data migration that involves copying data and metadata from a source storage array to a destination array, exchanging connection and management information, and using a replication engine to ensure uninterrupted access, allowing for seamless upgrades or replacements without downtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data migration is performed from source storage array to destination storage array, then storage array upgrading or replacement is achieved, but downtime occurs and host applications lose access to storage array
Solution Approach 1:
The patent applies preliminary action by performing data copying from source to destination storage array before the actual migration switch. The system creates a destination storage array, copies all data to it, and prepares metadata in advance. Only after the destination array is fully prepared does the system switch connections, eliminating downtime. This is evident in the steps where data is copied to destination array 16b before exchanging connections with hosts.
Solution Approach 2:
The patent uses an intermediary approach by introducing a destination storage array as a mediator between the source storage array and hosts. During migration, the destination array serves as the active storage while the source array is being replaced. The replication engine acts as an intermediary mechanism that maintains data synchronization and enables transparent switching without interrupting host access.
2Adaptability or versatility
If re-initialization and reconfiguration are performed during storage array replacement, then new storage array becomes operational, but host systems require reconfiguration and applications lose access
Solution Approach 1:
The patent applies copying by creating a complete replica of the source storage array's data and metadata structure in the destination storage array. The replication engine copies not only data but also metadata including connection information, management information, and extended storage functionality metadata. This allows the destination array to be operational immediately upon connection exchange without requiring host reconfiguration.
Solution Approach 2:
The patent implements universality by designing the destination storage array to assume all functions of the source array universally. It handles data storage, metadata management, connection handling, and extended storage functionalities simultaneously. The array name table and DNS table updates ensure the destination array responds to all host communications universally, eliminating the need for host-specific reconfiguration.
3Productivity
If metadata is not forwarded during data migration, then migration process is simpler, but storage application functionality is disrupted at destination array
Solution Approach 1:
The patent applies preliminary action by forwarding metadata from the source storage array to the destination storage array before the migration switch occurs. The replication engine identifies metadata LUNs and copies them to the destination array in advance, ensuring that when hosts switch connections, the destination array already possesses all necessary metadata for immediate operational continuity.
Solution Approach 2:
The patent uses the replication engine as an intermediary mechanism that not only copies data but also identifies, extracts, and forwards metadata between source and destination arrays. This intermediary process ensures that extended storage functionality metadata is transferred alongside data, maintaining application functionality without disrupting the migration workflow.
Data Source
AI summary
Described are systems and methods of migrating data and metadata from a source storage array to a destination storage array transparently with respect to a storage application executing on a host. The storage application provides particular storage functionality at the source storage array while using metadata during its execution. During a data migration event in which data resident in disks at the source storage array are fully copied to the destination storage array, metadata stored at the source storage array are copied to the destination storage array. After the data migration event, the destination storage array assumes the personality of the source storage array.