Hi there,
well this is not that easy to explain.
it's depending on the available I/O.
- do you have local Datastores?
- if non-local > you have FC/iscsi/nfs ?
- you have different Raid for the Datastores? Which Kind of Raid? (Raid1/5/6,....) How much Disk Slices you have inside the Raid?
you need to be aware that you have read I/O on the Source Datastore and write I/O on the Destination. and this is additional next to you're running Vm's
i would jump on the esxi console and checking esxtop. there you see best if the datastores having any Latency Issues. you could do then a Test-Svmotion outside of Business Times
thx
Max