vSphere SIOC w/mixed usage P4500's

[Northwoods]

We are currently running six P4500's nodes to feed both our ESXi 4.1 install and a couple of physical servers with raw iSCSI mappings. To enable SIOC you need the spindles dedicated for vSphere to use which would imply either moving everything virtual (while my preference is not practical for a few years) or splitting the SAN into two clusters. I'm just wondering what have others done?

[lando_uk]

From experience, its not a good idea to mix vmware and other `windows` workloads on the same cluster unless they are 10G nodes, even without using SIOC you'll experience weird latency problems. Because VMware hosts only read from a single node - If that node gets busy due to an external SQL job, it could cause slowdowns and latency problems on VMs in the datastore that uses that node as its gateway, and having SIOC monitoring IO wont help, as it only monitors IO within the esx environment and wont know about those external servers that might be using bandwidth.