What is considered, normal, high, slow and problematic disk IOPS levels? eg in ms?
"IOPS" is sure not measured in "ms". It is simply a number (input/output operations per second). Value depends on storage type (local/network), medium (hdd/ssd), concurrency of access (dedicated/shared), sequential/random, transfer size, etc, etc.
I assume: You are looking ideal IO latency value in ms.
Just for your info..VMware offers one cool feature SIOC (Storage IO control), which throttles the the LUN when there is IO contention, SIOC determines IO contention based on SIOC IO threshold(i.e. IO latency) & if data-store crosses the IO latency, SIOC starts throttling the LUN (i.e. distribute the IOPS based on IOPS shares assigned to each VM:::From UI or API you can assign IOPS shares to particular VM which is residing on datastore where SIOC is enabled)
Best practices to set this latency for SIOC is as follows:
Learn more about SIOC here: Storage IO Control, the movie - Yellow Bricks & Storage I/O Control, the basics
There is another cool feature VMware offers is SDRS which can balance the IO load across cluster of datastores. (Read more :An introduction to Storage DRS & :Death to false myths: Storage IO Control = SDRS IO load balancing
IOPS capacity depends on type of storage you are using: ie.FC(VMFS), iSCSI, NFS, local disks, vSAN, SSDs etc. IOPS values will be given by the storage vendors the way we get bike mileage values from bike vendors.
Hope this helps
I like to see storage latency below 5ms ... which is a completely different metric to throughput (MB/s) or IOPS.
These three metrics together allow you to measure performance baselines so that you know when you have an issue.
See example of my testing here;
EMC Symmetrix VMAX 40K testing on vSphere 5.0
Cheers,
Jon