Adaptive Throttling for Layered Storage Write Delays

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Solution Overview

Problem

Conventional layered storage systems face sub-optimal performance due to rate mismatches between data intake and flushing, leading to inconsistent delays and unfairness in write operations, as they often throttle writes when a layer is nearly full, causing significant delays and potential unmounting of network filesystems.

Innovation Solution

Implement an adaptive throttling scheme that monitors the flushing rate of a layer to set a maximum intake rate, applying rate-based throttling with fine granularity to maintain balanced data flow, adjusting the intake rate based on the flushing rate, data reduction ratio, and available processing or storage capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional throttling is applied when a layer is nearly full, then data overflow is prevented, but write operations experience significant and inconsistent delays

Engineering Contradiction:

Improvedata overflow preventionVSAvoidwrite operation delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements dynamic throttling by continuously monitoring the data rate between layers and adjusting the throttling intensity in real-time, rather than using static threshold-based throttling. This allows the system to adapt to changing workloads and maintain optimal performance while preventing overflow.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms where the monitored data rate from lower layers is used to control the ingest rate of upper layers. This closed-loop control ensures that throttling actions are based on actual system conditions, preventing both overflow and excessive delays.

Inventive Principle:

Principle #23Feedback

2Productivity

If high watermark throttling is used to slow ingest rate, then data flow is controlled, but fairness is compromised as some writes are penalized much more than others

Engineering Contradiction:

Improvedata flow controlVSAvoidwrite operation fairness

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

The patent changes the control parameter from binary threshold-based throttling to continuous rate-based throttling. By monitoring actual data rates and applying proportional throttling, the system achieves fair treatment of all write operations while maintaining effective data flow control.

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If significant delays are applied to control data rate, then layer capacity is protected, but system stability is compromised as network filesystems may unmount drives

Engineering Contradiction:

Improvelayer capacity protectionVSAvoidsystem stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies partial throttling by controlling the data rate to match the lower layer's capacity without completely stopping the data flow. This partial action is sufficient to prevent overflow while maintaining system stability and avoiding filesystem unmounting.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS11163449B2Adaptive ingest throttling in layered storage systems

Publication Date: 2021.11.02 EMC IP HLDG CO LLC

AI summary

A method of accepting writes in a multilayered storage system is provided. The method includes (a) monitoring a rate of flushing of data from a first data storage component to a second data storage component; (b) setting an intake rate for the first data storage component based on the monitored flushing rate; and (c) throttling writes to the first data storage component based on the set intake rate. An apparatus, system, and computer program product for performing a similar method are also provided.