In vSphere 4, when multiple Multipathing Plugins (MPPs) exist, the Pluggable Storage Architecture
(PSA) performs which of the following two tasks (Choose Two)?
A.
Manages physical path claiming and unclaiming
B.
Associates of physical paths with logical devices
C.
Implements logical device bandwidth sharing
D.
Provides logical device and physical path I/O statistics
Explanation:
Managing Multiple Paths inside VMware PSA (Pluggable Storage Architecture)To manage storage multipathing, ESX/ESXi users a special VMkernel layer, Pluggable Storage Architecture (PSA). The PSA is an open modular framework that coordinates the simultaneous operation of multiple multipathing plug-ins (MPPs).
The VMkernel multipathing plug-in that ESX/ESXi provides by default is the VMware Native Multipathing Plug-In (NMP).
The NMP is an extensible module that manages sub-plug-ins. There are two types of NMP
sub-plug-ins, Storage Array Type Plug-Ins (SATPs), and Path Selection Plug-Ins (PSPs). SATPs and PSPs can be built-in and provided by VMware, or can be provided by a third party.
If more multipathing functionality is required, a third party can also provide an MPP to run in addition to, or as a replacement for, the default NMP.When coordinating the VMware NMP and any installed third-party MPPs, the PSA performs the following tasks:
Loads and unloads multipathing plug-ins.
Hides virtual machine specifics from a particular plug-in.
Routes I/O requests for a specific logical device to the MPP managing that device.
Handles I/O queuing to the logical devices.
Implements logical device bandwidth sharing between virtual machines.
Handles I/O queueing to the physical storage HBAs.
Handles physical path discovery and removal.
Provides logical device and physical path I/O statistics.If MPP question is asked then..
The multipathing modules perform the following operations: VMware provides a generic Multipathing Plugin (MPP) calledNative Multipathing Plugin (NMP). What does MPP or NMP do?
Manage physical path claiming and unclaiming.
Manage creation, registration, and deregistration of logical devices.
Associate physical paths with logical devices.
Process I/O requests to logical devices:
Select an optimal physical path for the request.
Depending on a storage device, perform specific actions necessary to handle path failures and I/O command retries.
Support management tasks, such as abort or reset of logical devices.