Description:

As a new feature introduced in the 4.1 release of vSphere 4.1, Storage I/O control (SIOC) provides I/O prioritization for virtual machines running on a cluster of ESX servers that share a common pool of storage. During periods of high I/O congestion, SIOC will engage to dynamically adjust the I/O queue slots on each ESX server accessing that shared resource to align the available throughput to the prioritization of virtual machines runing on shared datastore. This paper explains the basic mechanics of how this new feature works and addesses considerations for use of this virtualization environments.