ESXi 5.5, 6.x IOPS Limit Not Working – Disk.SchedulerWithReservation

Last week, we went limit some our machines IOPS but we saw the limitation is not working on our machines, after searching the issue on VMware KB, we found an KB (2059192) that explain an known issue on ESXi 5.5 and ESXi 6.

It seems, disk IO scheduling model has been changed on the platforms and it’s cause of the issue.

But the solution is so simple, just you need to change an ESXi’s parameter:

Revert the disk I/O scheduler to an earlier version by using the vSphere Web Client

In the vSphere Web Client, edit the Disk.SchedulerWithReservation parameter in the Advanced System Settings list for the host.

1. Navigate to the host.
2. On the Manage tab, click Settings and click Advanced System Settings.
3. Locate the Disk.SchedulerWithReservation parameter.Note: You can use the Filter or Find text boxes to find the parameter easily.
4. Click Edit and set the parameter to 0.
5. Click OK.

Revert the disk I/O scheduler to an earlier version by using an ESXCLI command

In the ESXi Shell to the host, run this console command:

esxcli system settings advanced set -o /Disk/SchedulerWithReservation -i=0