You can use ESXCLI to enable or disable per file I/O scheduling.

By default, vSphere provides a mechanism that creates scheduling queues for each virtual machine file. Each file has individual bandwidth controls. This mechanism ensures that the I/O for a particular virtual machine goes into its own separate queue and does not interfere with the I/O of other virtual machines.

This capability is enabled by default. You can turn it off by using the esxcli system settings kernel set -s isPerFileSchedModelActive option.

Run esxcli system settings kernel set -s isPerFileSchedModelActive -v FALSE to disable per file scheduling.

Run esxcli system settings kernel set -s isPerFileSchedModelActive -v TRUE to enable per file scheduling.