You can increase the capacity of a VMFS datastore on the ESXi host. Additional capacity might be required when you add virtual machines to the datastore, or when the virtual machines running on the datastore require more space.

If a shared datastore has powered on virtual machines and becomes 100% full, you can increase the datastore capacity. You can perform this action only from the host where the powered on virtual machines are registered.
Depending on your storage configuration, you can use one of the following methods to increase the datastore capacity. You do not need to power off virtual machines when using either method of increasing the datastore capacity.
Expand an Existing Datastore
Increase the size of an expandable datastore. The datastore is considered expandable when the backing storage device has free space immediately after the datastore extent.
Add an Extent
Increase the capacity of an existing VMFS datastore by adding new storage devices to the datastore. The datastore can span over multiple storage devices, yet appear as a single volume.
The spanned VMFS datastore can use any or all its extents at any time. It does not need to fill up a particular extent before using the next one.
Note: Datastores that support only the hardware assisted locking, also called the atomic test and set (ATS) mechanism, cannot span over non-ATS devices. For more information, see vSphere VMFS Locking Mechanisms.

Prerequisites

You can increase the datastore capacity if the host storage meets one of the following conditions:
  • The backing device for the existing datastore has enough free space.
  • You added new storage devices to the host.

Procedure

  1. In the vSphere Client, navigate to the datastore.
  2. Select Increase Datastore Capacity from the datastore right-click menu.
  3. Select a device from the list of storage devices.
    Your selection depends on whether an expandable storage device is available.
    Option Description
    To expand an existing datastore extent Select the device for which the Expandable column reads YES.
    To add an extent Select the device for which the Expandable column reads NO.
  4. Review the Partition Layout to see the available configurations.
  5. Select a configuration option from the bottom panel.
    Depending on the current layout of the disk and on your previous selections, the menu items you see might vary.
    Menu Item Description
    Use free space to expand the datastore Expands an existing extent to a required capacity.
    Use free space Deploys an extent in the remaining free space of the disk. This menu item is available only when you are adding an extent.
    Use all available partitions Dedicates the entire disk to a single extent. This menu item is available only when you are adding an extent and when the disk you are formatting is not blank. The disk is reformatted, and the datastores and any data that it contains are erased.
  6. Set the capacity for the extent.
    The minimum extent size is 1.3 GB. By default, the entire free space on the storage device is available.
  7. Click Next.
  8. Review the proposed layout and the new configuration of your datastore, and click Finish.
    Note: It is recommended to perform a cluster level rescan at vCenter Server after you perform any form of expansion done at the host level. If you do not perform a cluster level rescan from vCenter Server, it may not detect any change. This causes a disparity in the current space/usage for the datastore.

    If the device where you increased the capacity is exposed to multiple hosts in multiple clusters, then the cluster level rescan must be triggered on all the clusters where the device is visible.