Decides, for every I/O sent to a storage device, which physical path it travels down, using policies like Round Robin, Fixed or Most Recently Used. It is one of the two submodules of NMP.
Also called Path Selection Plug-in.
Read more: Broadcom TechDocs
In the Ultra Transcenders books
Each book explains PSP in context, with comparison tables and the common traps.
Terms in this definition
- General-purpose v1
The older storage account kind (
Storage), which lacks access tiers, Archive and premium file shares and retires on 13 October 2026. Converting to ZRS requires first upgrading to GPv2, a one-way change. - Physical
Describes the concrete, real-world parts that put a logical architecture into effect.
- PATH
Parent-child hierarchies in DAX rely on this function. For each row it builds one delimited text value listing the IDs of the row's ancestors, top level first and ending with the row's own ID, which PATHITEM, PATHLENGTH and friends can then pick apart.
- LIKE
Compares strings with a pattern that can contain the % and _ wildcards. Because it only understands character patterns, searching big volumes of text this way is much slower than using full-text search.
- ROUND
Takes a number in DAX to a set count of digits, where a half always moves away from zero. Rounding before comparing Decimal Number values helps head off floating-point surprises.
- MRU
A multipathing path selection policy that sticks with the path currently in use and does not switch back when the preferred path recovers. In vSphere it is an NMP policy and the default for most active-passive storage arrays.
- NMP
Handles failover and path choice for SCSI storage through two kinds of submodule, SATP and PSP, and is VMware's default multipathing module. For NVMe devices, HPP is used instead.