I'm also wondering about enabling Storage IO Control. It's currently not enabled on the datastores. I know it's helpful for the StorageDRS, but will enabling it have any negative effects on the system?
SIOC is a great feature.. refer my blog for more info http://pibytes.wordpress.com/2013/01/19/magic-effect-of-sioc-vmware-storage-input-output-control-in-vsphere-5-a-practical-study/
but when it is used with VMware SRM there is one issue
If you have enabled the SIOC there may be a chance you will face
- This issue occurs when SRM cleans the production site for the failback in a Planned Migration.
- Site Recovery Manager 5.x unregisters the virtual machines in the production site and unmounts the VMFS volume.
Note: When you have Storage DRS enabled, Storage IO Control, virtual machines, or templates registered on the VMFS volume, vCenter is not able to unmount the VMFS volume, resulting in an error.
http://blogs.vmware.com/vsphere/2012/06/sioc-and-srm.html
You must verify the following conditions before you can successfully unmount the datastore:
- No virtual machines reside on the datastore.
- The datastore is not a part of a Datastore Cluster.
- The datastore is not managed by Storage DRS.
- Storage I/O Control is disabled for this datastore.
- The datastore is not used for vSphere HA Heartbeat.
refer the above for more info