File system metrics for ESX/ESXi hosts are collected periodically and used to populate VMware management objects. The interval of observation triggered by VMware is not under the immediate control of WhatsUp Gold monitoring, and sometimes a lag will appear in your reporting.

To work around measurements that are skewed due to normal or obvious lag by VMware, as outlined here, you can:

  • Use a vCenter in your environment. To avoid disk utilization measurements that are skewed due to normal or obvious lag by VMware, use a vCenter server in your VMware environment. Adding a vCenter requires discovering your virtual environment from vCenter (supply the vCenter address only) at discovery time.
  • Change the refresh interval (VMware). This involves changing a text file on each VMware ESX/ESXi host (/etc/vmware/hostd/config.xml) as detailed in this VMware knowledge base article. Change the <refreshInterval> property of the <datastore> element to a non-zero value to override the default interval of refresh (in minutes).
  • Refresh from vSphere. Where adding a vCenter to your virtual environment or changing the refresh interval on the VMware Host offer more permanent solutions, for a quick one-time ‘resync’ of datastore utilization reported from a single VMware ESX/ESXi host (information associated with DataStoreSummary.freeSpace, for example), you can open a vSphere client, connect to the ESX/ESXi host reporting suspect or stale values, and perform a storage refresh and rescan operation. The refreshed VMware values will be available to WhatsUp Gold within the Disk Utilization monitor’s normal polling interval. Alternatively, you can use the RealTime Performance monitor to check for the refreshed values. (If you have multiple VMware host devices in your environment, you will need to apply this refresh operation to each of them.)