Information Technology Reference
In-Depth Information
Figure 6.21
h e SATP for this
datastore is VMW_
SATP_ALUA_CX,
which is the default
SATP for EMC VNX
arrays.
Understanding MPP Modules
The MPP module can add signii cantly enhanced multipathing to vSphere, and for the given
LUNs it supports, it replaces the NMP, SATP, and PSP. The MPP claim policy (the LUNs that it
manages) is dei ned on a LUN-by-LUN and array-by-array basis, and MPPs can coexist with NMP.
Because it replaces the NMP, SATP, and PSP, the MPP can change the path selection normally
handled by the PSP. This allows the MPP to provide more sophisticated path selection than the
VMware-supplied PSPs can—including selecting by host queue depth and, in some cases, the
array target port state. As a result of this more sophisticated path selection, an MPP could offer
notable performance increases or other new functionality not present in vSphere by default.
The PSA was written not only to be modular but also to support third-party extensibility;
third-party SATPs, PSPs, and MPPs are technically possible. At the time of this writing, only
a few MPPs were generally available, though other vendors are likely to create third-party
SATPs, PSPs, and potentially full MPPs. Once the MPP is loaded on an ESXi host via the vSphere
Web Client's host update tools, all multipathing for LUNs managed by that MPP become fully
automated.
An Example of a Third-Party MPP
EMC PowerPath/VE is a third-party multipathing plug-in that supports a broad set of EMC and
non-EMC array types. PowerPath/VE enhances load balancing, performance, and availability using
the following techniques:
Search WWH ::




Custom Search