Asynchronous Storage Reclamation for Thin-Provisioned Volumes

Solution Overview

Problem

Conventional thin-provisioning solutions experience performance degradation and increased deletion time due to synchronous storage space reclamation, which can prevent volume restoration and inefficiently utilize storage resources.

Innovation Solution

Implementing a system that identifies deleted volumes, saves information about allocated storage space, and reclaims it asynchronously based on a policy, such as during idle I/O periods or upon request, to minimize interference with application I/O operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If storage space is reclaimed synchronously with volume deletion, then storage space can be reused immediately, but system I/O performance degrades and deletion time increases

Engineering Contradiction:

Improvevolume deletion timeVSAvoidsystem I/O performance

Core Design Contradiction:

Loss of timeVSProductivity

Solution Approach 1:

The system performs preliminary actions by marking storage blocks as reusable and recording their locations during the deletion operation, but delays the actual reclamation work until a later time when I/O performance requirements are less critical. This separates the deletion logic from the reclamation execution, allowing deletion to complete quickly while reclamation happens asynchronously in the background.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the reclamation timing based on system conditions and policy configurations. Instead of a fixed synchronous approach, the reclamation operation can be scheduled at different times depending on I/O workload, system priorities, and administrative policies, making the system adaptable to varying performance requirements.

Inventive Principle:

Principle #15Dynamics

2Quantity of substance

If storage space is reclaimed synchronously with volume deletion, then storage space availability improves, but the time required to delete a volume increases

Engineering Contradiction:

Improveavailable storage spaceVSAvoidvolume deletion time

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The system performs preliminary actions by marking storage blocks as reusable and recording their locations during the deletion operation, but delays the actual reclamation work until a later time when I/O performance requirements are less critical. This separates the deletion logic from the reclamation execution, allowing deletion to complete quickly while reclamation happens asynchronously in the background.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements self-service by maintaining metadata records of reusable storage blocks that can be automatically allocated to new volumes when needed. The thin-provisioning system automatically tracks and manages reusable space without requiring manual intervention or blocking deletion operations, allowing the system to serve itself efficiently.

Inventive Principle:

Principle #25Self-service

3Productivity

If storage space is reclaimed immediately upon deletion, then storage efficiency improves, but the ability to restore deleted volumes is lost

Engineering Contradiction:

Improvestorage efficiencyVSAvoidvolume restoration capability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system performs preliminary actions by marking storage blocks as reusable and recording their locations during the deletion operation, but delays the actual reclamation work until a later time when I/O performance requirements are less critical. This separates the deletion logic from the reclamation execution, allowing deletion to complete quickly while reclamation happens asynchronously in the background.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system provides a cushioning period by maintaining the storage blocks in a reusable but not yet reclaimed state. This intermediate state acts as a safety buffer that allows for potential volume restoration while still preparing the space for future use. The delayed reclamation provides a window of opportunity to recover accidentally deleted volumes before the space is permanently reallocated.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS8635422B1Systems and methods for reclaiming storage space from deleted volumes on thin-provisioned disks

Publication Date: 2014.01.21 ARCTERA US LLC

AI summary

A computer-implemented method for reclaiming storage space from deleted volumes on thin-provisioned disks may include: 1) identifying a deleted volume, 2) identifying storage space on a thin-provisioned disk that was allocated to the deleted volume, 3) saving information that identifies the storage space, 4) identifying a policy that specifies reclaiming the storage space asynchronously with respect to the deleted volume, and then 5) reclaiming the storage space asynchronously with respect to deletion of the volume in accordance with the policy. Various other methods, systems, and computer-readable media are also disclosed.