Cross-Cluster Write-Back Caching with Threshold Management

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Solution Overview

Problem

Current systems face performance limitations in write-back caching within and across clusters, leading to increased write latency and decreased throughput, especially for large datasets, and struggle to maintain data consistency across scenarios like shutdowns and reboots.

Innovation Solution

The implementation of methods and systems that enable write-back caching across clusters by managing cache thresholds, payload sizes, and idle thresholds to optimize write operations, ensuring efficient data handling and consistency through tunable parameters and synchronization mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If write-back caching is implemented across clusters, then write latency is reduced and throughput is increased, but data consistency and system reliability become more difficult to maintain

Engineering Contradiction:
Improvewrite throughputVSAvoiddata consistency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements feedback mechanisms through write delegations and cache metadata that track the state of cached data across clusters. The system monitors cache validity, tracks write operations, and provides feedback signals to coordinate write-back operations, ensuring data consistency is maintained even as write throughput increases across distributed clusters.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces intermediary mechanisms including write delegations from volume to cache, and metadata structures that mediate between the cache and underlying storage systems. These intermediaries coordinate write operations across clusters, allowing high throughput while maintaining consistency through controlled access and state tracking.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of time

If write-back caching is implemented across clusters, then write latency is reduced, but system complexity increases

Engineering Contradiction:
Improvewrite latencyVSAvoidcaching system complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent segments the caching system into distinct functional components: write delegations, cache metadata, threshold monitoring mechanisms, and write-back coordination layers. This segmentation allows each component to handle specific aspects of the write operation independently, reducing overall system complexity while maintaining low write latency through specialized optimization at each level.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary actions by establishing write delegations and setting cache thresholds before write operations occur. Write metadata is prepared in advance, and delegation relationships are pre-configured, allowing the system to quickly process write requests with minimal latency while the complex consistency management is handled by pre-established structures.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If cache thresholds and payload sizes are tuned for optimal performance, then throughput is maximized, but adaptability to different workloads decreases

Engineering Contradiction:
Improvewrite throughputVSAvoidworkload adaptability
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic threshold and payload size adjustment mechanisms that automatically adapt to different workload characteristics. The system monitors write patterns, cache hit rates, and workload intensity, then dynamically tunes cache file thresholds, cache thresholds, and payload sizes to optimize throughput for each specific workload while maintaining adaptability across diverse workloads.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS20240329878A1Write-Back Caching Across Clusters
Publication Date: 2024.10.03 NETAPP INC
  • US20240329878A1 patent drawing
  • US20240329878A1 patent drawing
  • US20240329878A1 patent drawing

AI summary

A method, computing device, and non-transitory machine-readable medium for write-back caching within a same or different clusters. A client write request to write data to a volume (for which the client has mounted the corresponding cache) may be received at a network module of a node and processed to generate a write request that can be forwarded to a disk module hosting the cache (at a same or different node than received the client write request). The data is written to the cache and confirmation of the write is sent to the client. Accumulated data in the cache is written back to the volume (hosted by a different node than the cache) when at least one of a cache file threshold or a cache threshold is met. These parameters are set to values that reduce write latency, increase throughput, and help ensure data consistency and resiliency.