VMWARE: Increase the capacity of a VMFS datastore

After increasing the Lun on a SAN a simple rescan will not work within Virtual Center.  The process to make the new extended size show up in Virtual Center starts by logging directly into a ESX host that connects to the LUN.
To increase the capacity of a VMFS datastore:
   1. In vCenter Server, select the Datastores view.
   2. Select the datastore you want to grow and identify the host that has more virtual machines running on it.
   3. Open another vSphere client that connects directly to the ESX host.
   4. Go to Configuration > Storage adapters and perform a rescan. For more information, see Performing a rescan of the storage on an ESX/ESXi host (1003988).
   5. Go to Configuration > Storage, click the datastore that you want to grow, and click Properties.
   6. Ensure that the new size of the device is listed in the Extent Device list. If the increased size is not reflected, review the changes on the storage array and rescan again.
   7. Click Increase.
   8. Select a device from the list of storage devices for which the Expandable column is Yes and click Next.
   9. Set the capacity for the extent. The default capacity for the extent is the entire free space on the storage device. VMware recommends you to use the default setting.
   10. Click Next.
   11. After the process completes, go to vCenter Server, right-click the cluster that sees the expanded datastore, and click Rescan for Datastores. For more information, see Performing a rescan of the storage on an ESX/ESXi host (1003988).
   12. If there are other hosts that see the expanded datastore, perform a rescan on these hosts also.

Note: If the LUN experiences a high I/O throughput when growing the VMFS, the ESX host may not be able to complete the operation. In such a case, repeat the process during non-business hours and when backup operations are not running. If the problem persists, power off some of the virtual machines residing on the LUN and then retry.

By: VMWARE