Administrator Guide

VMware vSphere and Live Volume
52 Dell EMC SC Series: Synchronous Replication and Live Volume | CML1064
8.3 Fixed
The Fixed PSP may be desirable when a preferred path on the storage fabric should be used. The Fixed PSP
may also be useful in a uniform Live Volume storage presentation, if the ALUA feature (added in SCOS 7.3) is
not yet available, in order to avoid sending read and write I/O down a non-optimal path to the secondary Live
Volume. As shown in Figure 44, the MPIO policy on the vSphere host should be set to Fixed with the
preferred path leading to the primary Live Volume. Using the Fixed PSP generally requires more
administrative effort to implement, maintain, and document.
Fixed policy
8.4 Single-site MPIO configuration
In a single-site or uniform configuration, vSphere hosts may be zoned to both arrays. If a Live Volume is
mapped over both arrays to the vSphere hosts, the volume can participate in an MPIO configuration involving
both arrays. In a Live Volume configuration, the optimal I/O path is through the primary Live Volume. In this
scenario, using the vSphere Round Robin MPIO policy in conjunction with the Live Volume ALUA feature
ensures I/O traffic goes through the primary Live Volume array. This is a preferred configuration because it
requires minimal administrative effort and yields a well-balanced fabric.
Alternatively, the vSphere Fixed MPIO policy with preferred path can be used to ensure front-end I/O traffic is
going through the primary Live Volume array. In the event a Live Volume role swap occurs, the preferred path
will need to be updated on each vSphere host to point to an optimal primary Live Volume path. This is where
additional administrative effort is involved to maintain a well-balanced fabric.