Storage System SLO Enforcement for Virtual Machines
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Solution Overview
Problem
Current data storage systems lack effective cross-host enforcement of service level objectives (SLOs) for virtual machines, leading to disparate priority treatments and resource mismanagement across different host systems, resulting in inefficient I/O operations and resource allocation.
Innovation Solution
Associating SLOs defined on a storage system with virtual machines, allowing the storage system to manage and enforce these objectives across multiple hosts, ensuring consistent priority and resource allocation by communicating SLOs through a virtualizer control station and multi-path driver, and persisting assignments even after host reboots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If service level objectives are enforced individually on each host system, then each host can manage its own virtual machines, but consistent priority treatment across different host systems cannot be achieved
Solution Approach 1:
The patent merges SLO enforcement functionality from individual host systems into a centralized storage system. The storage system now maintains SLO definitions and enforcement logic, coordinating across multiple hosts to ensure consistent priority treatment. This eliminates the fragmentation problem where each host independently enforced SLOs with potentially different interpretations.
Solution Approach 2:
The storage system acts as an intermediary between multiple host systems and the underlying storage resources. It receives SLO definitions, distributes them to relevant hosts, and coordinates enforcement across the storage network. This intermediary role ensures that all hosts apply the same SLO policies consistently regardless of vendor differences.
2Duration of action of stationary object
If SLO assignments are stored only on host systems, then host systems can manage their virtual machines, but assignments are lost after host reboots
Solution Approach 1:
The patent implements local caching of SLO assignments on host systems while maintaining the master copy on the storage system. Each host stores a local copy for quick access during operation, but the definitive assignment data resides on the storage system. This ensures both fast local enforcement and persistent storage that survives host reboots.
Solution Approach 2:
The storage system pre-defines and stores SLO assignments before hosts need them. When hosts boot up, they retrieve their SLO assignments from the storage system rather than having to recreate or reconfigure them. This preliminary preparation ensures assignments persist across reboots without requiring complex backup mechanisms.
3Adaptability or versatility
If multiple vendors' host systems access the storage system, then resource sharing is enabled, but disparate priority treatments occur
Solution Approach 1:
The storage system implements a universal SLO enforcement mechanism that works across multiple vendor platforms. By centralizing SLO management and using standardized protocols for SLO definition and enforcement, the system achieves multi-vendor compatibility while maintaining consistent priority treatment. The same SLO policies apply regardless of which vendor's host system accesses the storage resources.
Data Source
AI summary
Service level objectives (SLOs) defined for a storage system are associated with virtual machines running on hosts. For an I/O operation for a virtual machine (VM) running on a host system, storage processing is performed on the I/O operation in accordance with the SLO defined for the VM. The same storage system-defined SLOs may be applied to VMs running on multiple host systems. SLOs may be maintained by the storage array and shared with one or more host systems in I/O communication with the storage system. SLOs may be defined using a user interface of a storage system, host system, virtualizer control station or other component of a storage network, and communicated to the storage system, which may maintain the SLOs, and may disseminate them to one or more hosts. The SLOs then may be associated with VMs running on the hosts and tagged to I/O communications corresponding to the VMs.