Choosing the best SIOC latency threshold
Storage I/O Control extends the constructs of shares and limits to handle storage I/O resources. Storage I/O Control is a proportional share IOPS scheduler that, under contention, throttles IOPS. You can control the amount of storage I/O that is allocated to virtual machines during periods of I/O congestion. Controlling storage I/O ensures that more important virtual machines get preference over less important virtual machines for I/O resource allocation.
There are two thresholds: one for standalone Storage I/O Control and one for Storage DRS. For Storage DRS, latency statistics are gathered by Storage I/O Control for an ESXi host and sent to vCenter Server and stored in the vCenter Server database. With these statistics, Storage DRS can make the decision on whether a virtual machine should be migrated to another datastore.
The default latency threshold for Storage I/O Control is 30 milliseconds. The default setting might be acceptable for some storage...