Administrator Guide

VMware vSphere and Live Volume
49 Dell EMC SC Series: Synchronous Replication and Live Volume | CML1064
8 VMware vSphere and Live Volume
When vSphere and Live Volume combine, they can provide VMware-certified, large-scale application and
service mobility, high availability, planned maintenance, resource balancing, disaster avoidance, and disaster
recovery options for virtual environments.
8.1 Path Selection Policies (PSP)
vSphere ships with three MPIO path selection policies (PSP): Fixed, Round Robin, and Most Recently
Used (MRU is not tested and should not be used with SC Series storage). The best path selection policy to
choose with Live Volume depends on uniform or non-uniform storage presentation, available ALUA support,
replication type, latency between sites or arrays, and customer preference. Round Robin is largely the easiest
PSP to configure and provides both optimal I/O performance and balance of the storage fabric in uniform
storage presentations with ALUA support or non-uniform storage presentation with or without ALUA support.
8.2 Round Robin with Live Volume ALUA
Figure 42 depicts a Round Robin policy with a uniformly presented Live Volume between two SC Series
arrays with the ALUA feature (introduced in SCOS 7.3). Read and write I/O will follow the Round Robin policy,
taking optimal paths directly to the primary Live Volume, shown as Active (I/O), in a uniform Live Volume
storage presentation. Non-optimal paths lead to the secondary Live Volume and will be reserved for use in
the event all optimal paths to the primary Live Volume become unavailable. In the event of a Live Volume role
swap, the non-optimal paths reported by the SC Series array become optimal, and the optimal paths become
non-optimal.
Round Robin policy