Pluggable Storage Architecture (PSA) Package

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The Pluggable Storage Architecture (PSA) Framework package allows partners to deliver performance-enhancing, multi-pathing and load-balancing behaviors optimized per array.

Package Overview

vSphere has a special VMkernel layer called Pluggable Storage Architecture (PSA) Framework to manage storage multi-pathing. This PSA package is an open modular framework that coordinates the simultaneous operation of multiple plugins. PSA is a collection of VMkernel APIs that allow partners to insert code directly into the ESX storage I/O path. This allows partners to design their own load balancing techniques and failover mechanisms for a particular storage array.

Partner can develop three kinds of plugins - Multi-Pathing Pluin (MPP), Storage Array Type Plug-ins (SATPs), and Path Selection Plug-ins (PSPs). MPPs, SATPs and PSPs are referred to as Multipathing Extension Modules (MEMs). MEMs allow partners to enable new storage array support asynchronous to ESX releases and to deliver performance-enhancing, multi-pathing failover/failback semantics, and load-balancing behaviors optimized per array.The Pluggable Storage Architecture (PSA) package offers a comprehensive set of tools and resources to help storage hardware vendors develop the MEMs.

VMware provides a generic Multi-pathing Plugin (MPP) called Native Multi-pathing Plugin (NMP) that ships with vSphere and is the default multipathing. VMware's NMP is an extensible module that allows two kinds of plug-ins to be built on it: SATPs and PSPs. These plugins can be built-in and provided by VMware, or can be provided by a partner. If more multi-pathing functionality is required, a partner can also provide an MPP to run in addition to, or as a replacement for, the default VMware's NMP. SATPs and PSPs built from one vendor's MPP does not work for another vendor's MPP.

The MPP plugin manages physical path claiming and unclaiming; registers and de-registers logical devices; associates physical paths with logical devices; processes I/O requests to logical devices such as load balancing and handling failures and retry requests; and supports management tasks such as abort or reset of logical devices.

Product Versions Supported

This package supports the following product versions:

vSphere

4.0, 4.1, 5.0, 5.1, 5.5

Target Audience

  • Storage partners

Related Programs and Services

PSA Development Consulting

SDDC Foundation program (Storage Hardware Certification)

* - Going forward vStorage APIs for MultiPathing (VAMP) terminology will not be used. It would be strictly Pluggable Storage Architecture (PSA).

Documentation and Reference

Name Size  
Program Guide 448.6 KB
PSA Questionnaire 46.9 KB