To check that your VMs have loaded and are running the VMware Memory Balloon driver in the guest OS, you can use esxtop.
- Connect to your ESXi host using vMA, the DCUI or PuTTy (needs SSH service running) and run esxtop.
- Switch to the Memory page (press M)
- Press F to add a field
- Press J to add the field “MCTL = MEM Ctl (MB)”
- Press space to return to the main memory view page of esxtop.
- In the new MCTL? column, look at the list of VMs – a “Y” means that the driver is loaded and running whereas a “N” means that the balloon driver is not present.
This can be useful to double check things if you run into a problem troubleshooting memory ballooning issues as I have seen cases where VMware Tools reports as “OK” for the VM but the balloon driver is not running when viewed in esxtop.
