6.7

Table Of Contents
The MPP claim rules are ordered. Lower rule numbers have preference
over higher rule numbers. The NMP claim rules are not ordered.
Table 181. Multipathing Acronyms
Acronym Definition
PSA Pluggable Storage Architecture
NMP Native Multipathing Plug-in. Generic VMware multipathing
module.
PSP Path Selection Plug-in. Handles path selection for a given
device.
SATP Storage Array Type Plug-in. Handles path failover for a given
storage array.
MPP (third-party) Multipathing Plug-in. A multipathing module developed and
provided by a third party.
HPP Native High-Performance Plug-in provided by VMware. It is used
with ultra-fast local flash devices.
About Pluggable Storage Architecture
Pluggable Storage Architecture (PSA) is an open and modular framework that coordinates various
software modules responsible for multipathing operations.
VMware provides generic native multipathing modules, called VMware NMP and VMware HPP. In
addition, the PSA offers a collection of VMkernel APIs that third-party developers can use. The software
developers can create their own load balancing and failover modules for a particular storage array. These
third-party multipathing modules (MPPs) can be installed on the ESXi host and run in addition to the
VMware native modules, or as their replacement.
When coordinating the VMware native modules and any installed third-party MPPs, the PSA performs the
following tasks:
n
Loads and unloads multipathing plug-ins.
n
Hides virtual machine specifics from a particular plug-in.
n
Routes I/O requests for a specific logical device to the MPP managing that device.
n
Handles I/O queueing to the logical devices.
n
Implements logical device bandwidth sharing between virtual machines.
n
Handles I/O queueing to the physical storage HBAs.
n
Handles physical path discovery and removal.
n
Provides logical device and physical path I/O statistics.
vSphere Storage
VMware, Inc. 208