VMware just published a video demonstrating how the new Storage I/O Control (SIOC) feature, part of the upcoming vSphere 4.1, works.
SIOC provides the capability to define quality of service prioritization for the I/O activity on a single host or a cluster of hosts.
The prioritization, which can be enable or disable on specific datastores, is enforced through shares and limits.
The ESX/ESXi hosts monitors the latency in communication with the datastore of choice. As soon such latency exceeds a defined threshold the datastore is considered congested.
At that point all VMs accessing that datastore are prioritized according to their defined shares.
The administrator can even define the amount of I/O operations per second (IOPS) that each virtual machine can reach.
The video shows SIOC in action and it’s really worth watching:
A couple of weeks ago virtualization.info published some unreleased, official information from VMware about the performance improvements introduced by vSphere 4.1, and the list includes SIOC.
Thanks to Yellow Bricks for the news.