Local Lock Semantics for Active-Active Storage Clusters
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Solution Overview
Problem
Active-Active storage clusters face performance limitations due to the need for node synchronization to ensure consistent access and update of data and metadata objects, which requires resource-intensive internode exchanges and can increase latency and lock contention.
Innovation Solution
Implementing a local lock semantics schema where each node acquires local locks independently before sending a commit message, eliminating the need for internode lock synchronization and reducing the protected section's duration, thus optimizing resource usage and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nodes are synchronized to guarantee consistent access/update of data and metadata objects, then data consistency is improved, but cluster performance deteriorates
Solution Approach 1:
The patent segments the locking mechanism into local locks at each node rather than using global locks that require internode synchronization. Each node independently acquires and releases locks on its local metadata pages, eliminating the need for coordinated synchronization between nodes while maintaining consistency within each node's local state.
Solution Approach 2:
The patent applies local quality by implementing lock semantics that are specific to each node's local state rather than requiring uniform global locking. Each node manages its own lock state independently, allowing local optimization without compromising overall system consistency. The lock duration is localized to each node's critical section, reducing the time locks are held and minimizing contention.
2Reliability
If internode lock synchronization is used to ensure consistent access, then data consistency is improved, but resource consumption increases
Solution Approach 1:
The patent extracts the synchronization requirement from the locking mechanism itself. Instead of using locks that require internode synchronization, the patent removes the synchronization dependency by using local locks that are managed independently at each node. The commit message mechanism handles consistency without requiring lock coordination between nodes, effectively taking out the problematic synchronization aspect.
Solution Approach 2:
Each node serves itself by independently acquiring, holding, and releasing locks on its local metadata pages without requiring assistance or coordination from other nodes. The local lock mechanism is self-contained, with each node managing its own lock state and critical sections autonomously, eliminating the need for resource-intensive internode lock synchronization protocols.
3Reliability
If global locks are used for metadata pages, then data consistency is improved, but lock contention increases
Solution Approach 1:
The patent segments the lock scope from global to local, dividing the previously unified lock management into independent local lock instances at each node. This segmentation allows multiple nodes to hold and release locks simultaneously without contention, as each node's locks are independent. The critical section duration is reduced because locks are released locally without waiting for internode synchronization.
Solution Approach 2:
Nodes acquire local locks on metadata pages before sending commit messages, performing the locking action preliminarily and independently. This preliminary action allows the lock to be held for the minimal necessary duration at each node, reducing the overall lock contention period. The commit message transmission and lock release are decoupled, allowing locks to be released as soon as the local critical section is complete.
Data Source
AI summary
A method, computer program product, and computer system for acquiring, by a first node, local locks of the first node associated with a metadata log transaction, wherein the first node acquires the local locks of the first node prior to sending a commit message to a second node. The second node may acquire local locks of the second node associated with the metadata log transaction, wherein the second node acquires the local locks of the second node based upon, at least in part, receiving the commit message from the first node.