Disabling VAAI is a not a recommended solution to your problem. By putting the entire datastore in maintenance mode, you are telling SDRS to evacuate all of the VMs, which can result in multiple simultaneous Storage vMotions. This can result in tremendous storage and network traffic being generated.
Assuming the issue is related to overwhelming the storage, I would recommend setting the Maximum Cost for the datastores in question to 32, which would allow a maximum of 2 concurrent Storage vMotions (given that the cost for a Storage vMotion is 16).
This article does a good job discussing the details around what I've just discussed, including where to change the settings.
This article lists the varioius default values: vMotion/Storage vMotion Cost values