Storage System Heartbeat Monitoring for Failover Resumption

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Solution Overview

Problem

Current multi-site distributed data storage systems face challenges in reducing resumption time for I/O operations during automatic unplanned failover from a primary to a secondary mirrored storage system, due to delays in failure detection, serial health-check operations, redundant operations, and system resource contention.

Innovation Solution

The solution involves monitoring heartbeat information at ultra-short intervals, optimizing health check operations through multi-level parallelization, avoiding redundant operations using caching, reducing contention by batching operations, minimizing system calls and context switches through prefetching, and facilitating early-abort of conflicting workflows.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If heartbeat information is monitored at traditional time intervals during failover, then system resource consumption is reduced, but failure detection time increases leading to longer I/O resumption time

Engineering Contradiction:
ImproveI/O resumption timeVSAvoidsystem resource consumption
Core Design Contradiction:
Loss of timeVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts heartbeat monitoring intervals based on system state. During normal operation, traditional intervals are used to conserve resources. During failover detection, the interval automatically shortens to ultra-short intervals for rapid detection, then returns to normal after failover completion, optimizing the balance between detection speed and resource consumption throughout the operational cycle

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system prepares ultra-short interval monitoring in advance by having the capability ready but not actively executing it during normal operation. When failover conditions are detected, the pre-configured ultra-short interval mechanism is immediately activated, enabling rapid failure detection without the overhead of continuously running high-frequency monitoring

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If health check operations are performed serially during failover, then system complexity is reduced, but failover latency increases

Engineering Contradiction:
Improvefailover latencyVSAvoidsystem complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The health check operation is divided into multiple independent parallel tasks that can execute simultaneously. Different health check functions (e.g., connectivity checks, data integrity checks, service status checks) are segmented into separate operations that run in parallel, reducing total failover latency while maintaining manageable complexity through modular task design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from single-threaded sequential health checking to multi-threaded parallel health checking, adding the dimension of concurrent execution. This dimensional change allows multiple health check operations to proceed simultaneously rather than one after another, significantly reducing failover latency while the threading infrastructure manages the increased complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If redundant health check operations are performed during failover, then failure detection accuracy is improved, but failover latency increases

Engineering Contradiction:
Improvefailure detection accuracyVSAvoidfailover latency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

Health check results and system state information are cached in advance during normal operation. When failover is triggered, the cached information is immediately utilized to avoid redundant checks, providing accurate failure detection without the time penalty of repeating all health check operations, thus reducing failover latency while maintaining detection accuracy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system discards redundant health check operations by utilizing previously obtained health check results and cached system state information. Instead of performing all health checks again during failover, the system recovers and reuses valid cached data, eliminating unnecessary repetition while maintaining accurate failure detection

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 3:

During failover, the system performs a selective subset of health check operations rather than all possible checks. Critical path health checks are executed immediately while less critical checks are deferred or skipped, providing sufficient detection accuracy for the failover context without the full time cost of comprehensive checking

Inventive Principle:
Principle #16Partial or excessive action

4Loss of time

If system calls and context switches are频繁 performed during failover, then operational flexibility is improved, but I/O resumption time increases

Engineering Contradiction:
ImproveI/O resumption timeVSAvoidoperational flexibility
Core Design Contradiction:
Loss of timeVSEase of operation

Solution Approach 1:

Critical data and configuration information are pre-loaded into memory and prepared in advance before failover occurs. During the actual failover process, the system operates with this pre-loaded information, minimizing the need for additional system calls and context switches. This preliminary preparation reduces I/O resumption time while the pre-loaded data maintains operational flexibility

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Multiple system calls and context switch operations are merged and batched together during failover. Instead of performing numerous individual system calls sequentially, the system combines related operations into fewer bulk operations, reducing the total number of context switches and thereby reducing I/O resumption time while maintaining the necessary operational flexibility through the combined operations

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS20250165359A1Methods and systems to improve input/output (i/o) resumption time during a non-disruptive automatic unplanned failover from a primary copy of data at a primary storage system to a mirror copy of the data at a cross-site secondary storage system
Publication Date: 2025.05.22 NETAPP INC
  • US20250165359A1 patent drawing
  • US20250165359A1 patent drawing
  • US20250165359A1 patent drawing

AI summary

Multi-site distributed storage systems and computer-implemented methods are described for improving a resumption time of input/output (I/O) operations during an automatic unplanned failover (AUFO). A computer-implemented method includes monitoring, with a second cluster, heartbeat information received at ultra-short time intervals from a first connection of one or more storage objects of the first cluster, determining, with the second cluster, whether the heartbeat information from the first connection is received during an ultra-short time interval, and intelligently routing heartbeat information from the one or more storage objects of the first cluster from the first connection to a second connection when the heartbeat information from the first connection is not received during the ultra-short time interval.