Dell Storage with Microsoft Storage Spaces Best Practices Guide

Some processing capability must be reserved for the Hyper-V host server so that Storage Spaces and the remaining roles and features running on the server perform as expected. For each server, Dell recommends at least two logical processors be left unallocated to VMs so that they remain available for the Hyper-V host server.

Also, Dell recommends that you design the solution such that in the event of a potential compute node failure when the VMs fail over to the remaining compute nodes, that the logical processor resources in those nodes are able to handle the additional VM load. Dell recommends that the number of logical processors allocated to all VMs hosted by the compute cluster not exceed the number of available logical processors for each node multiplied by the total number of nodes minus one, as shown in the following equation:

Total Number of processors available for VMs=(Logical Processors available Per Node –2)* (Total # of nodes –1)

For example, a three-node Converged cluster, with 32 logical processors on each node and where two logical processors are reserved for each node, supports up to (32-2)*(3-1) = 60 logical processors available for allocation to all VMs. If each VM was configured to use only one logical processor, the solution could support up to 60 total VMs, or 20 VMs per node.