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Cannot extend datastore through vCenter Server (1011754)

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  • You cannot extend a datastore when vSphere Client is connected to vCenter Server.
  • vCenter Server does not show available unused space.
  • The SAN LUN is extended and the new storage appears under Storage Adapters when viewed in vCenter Server. When you extend the datastore through the datastore properties, the free space does not appear.
  • You can extend a datastore when vSphere Client is connected directly to the ESX host.


This article provides steps to work around the issue if you are unable to extend a datastore when vSphere Client is connected to vCenter Server.


vCenter Server calls a specific function to get all the available extents for that datastore. After getting extents, vCenter Server displays the extents as available if they meet these criteria filters:
  • LUNS are not used as datastores on that host or on any other host (with exceptions to force mounted volumes).
  • LUNS are not used as Raw Device Maps(RDMs) on that host or any other host.
vCenter Server applies these filters to stop any possible data corruption on already used LUNs by other host.
VMware recommends you to not to turn off the filters. Before making any changes to the LUN filters, contact the VMware Support team. For more information, see Turn off Storage Filters section in VMware vSphere 5.1 Documentation Center or VMware vSphere 6.0 Documentation Center.
When you connect directly to the ESX host, these filters do not exist and hence you can see the extents.
To work around the issue:
  1. Connect to the ESX host using vSphere Client and log in as root.
  2. Extend the datastore from the GUI.
  3. Rescan all hosts from vCenter Server.


vmware cannot increase datastore size, resize vmdk, resize disk, expand disk

See Also

Update History

09/08/2014 - Added ESXi 5.5 and vCenter Server 5.5 to Products

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