I/O control troubleshooting
In vSphere infrastructure storage, I/O usage of virtual machines can be controlled by Storage I/O control (SIOC). SIOC delivers storage I/O performance isolation of virtual machines. You can easily run important workloads using SIOC in virtualized storage infrastructure while it stops heavy I/O used virtual machines from impacting on less I/O used virtual machines. You can also allocate a preferred I/O resource for virtual machines using SIOC during bottlenecks. In addition, SIOC can be used to alleviate the poor performance of critical workloads because of I/O bottlenecks and latency in peak times. Some of the features of SIOC are as follows:
SIOC is disabled by default and needs to be enabled for each datastore in your vSphere infrastructure
It has a default latency threshold of 30 MS
It uses disk shares to allocate I/O queue slots
It does not intervene until the congestion latency threshold is reached and a percentage of the peak performance of a datastore is affected...
