Example Architectural Decision – vSphere Path Selection Plugin (PSP) for IBM SVC Storage

Problem Statement

What is the most suitable multipathing policy when using IBM SVC storage?


1. Ensure maximum performance and availability for vSphere storage
2. Ensure storage performance is as consistent as possible


1. IBM SVC Storage which is Active/Active
2. VAAI is supported and enabled


1. Solution must be supported


1. Ensure optimal performance and redundancy
2. Minimize Latency

Architectural Decision

Use vSphere Native Multipathing Plugin (NMP) and configure “VMW_PSP_RR” (Round Robin) as the path selection policy.

Set the default PSP to “VMW_PSP_RR” (Round Robin) for SATP VMW_SATP_SVC so all new LUNs automatically use Round Robin


1. Round Robin helps ensure minimum average latency to the storage by using all available paths
2. Ensure performance is not degraded for some/all virtual machines due to a single HBA or connection being heavily utilized
3. Using “VMW_PSP_ FIXED” requires the paths to be manually load balanced to avoid thrashing a single path
4. Using “VMW_PSP_MRU” or “VMW_PSP_ FIXED” may lead to incosistent performance across the LUNs due to some paths being more heavily used than others
5. There is no MPP currently supplied by IBM for SVC storage
6. Round Robin is a supported configuration (Note: Although not specifically listed in the Compatability Matrix)


1. Use “VMW_PSP_FIXED” (Default) – Fixed Pathing
2. Use “VMW_PSP_MRU”  – Most Recently Used
3. Use vendor supplied Multipathing Plugin


1. None