Thanks for the info!
I think you are right, overnight there could be some jobs (such as backup, update, virus-scan etc) that cause high disk IOPS.
285 IOPS is pretty high, I think - that could require investigation. What application runs inside that VM? However there are many factors, and you can decide that it is normal for your environment (especially if it does not stay around 285 all the time)
If you look at the VM Disk I/O Dashboard (in VMware Virtual Machine\ Performance Views) - how long do these VMs stay above 100 IOPS? How many samples? (5 mins by default).
If you look at the Host Disk I/O Dashboard (in VMware ESX Host Server\ Performance Views) - what is the totalDiskIOPS at the host level during these times?
If you drill-down into \disk performance views you can also see diskIOPS for each Host vmhba.
You might find after investigation that you can re-schedule VM backup jobs, virus-scans or patching/updates so that VMs on same Host, or same storage, do not all demand high disk I/O at the same time.
This is one purpose of the nworks MP - to help you optimise your environment
But anyway, you also have the option of using SCOM Override(s) if you decide that the high IOPS values are normal operation for you. You can -
1. increase the default threshold of 100
2. increase the default sample count of 2
Please let me know how it goes - this is great feedback for me!