Configuring a Global Placement Strategy

This topic details how to customize the default global placement strategy for new services.

Customizing priorities for Intelligent Placement

Access through:

Configuration menu > Self-Service > Placement tab

Available to:

Commander role of Superuser

When Commander predicts and selects the best deployment destination for a new service request, it first filters out invalid destinations. Each valid destination is then rated, based on the following criteria:

  • Quota: How much quota is available on this destination for the requester and the requester's organization, when per-destination quota is configured?
  • Cost: How much will this service cost on this destination? To learn how Commander calculates the cost of a service, see How Much Services Cost
  • Placement attributes: Does this destination provide the capabilities preferred for this service? To learn how to create and apply placement attributes, see Configuring Attributes for Intelligent Placement.

See How Intelligent Placement Works to learn how placement decisions are made and why Commander placed a service in a particular destination.

By default, these three factors are prioritized in the order they appear above, but if cost is more important to you than quota, for example, you can customize the priority.

  1. On the Placement tab, select Placement Strategy.
  2. In the Placement Priority section, use the up and down arrows to re-order the placement priorities.
  3. Click a placement priority to display helper text.

  4. Click Save to apply your changes.

Configuring datastore placement

Datastore Placement settings apply to vCenter and SCVMM managed systems.

About storage reservation

Commander reserves storage as soon as deployment of a new service request or fulfillment of a change request starts. This is true for manual deployment and fulfillment, automated deployment and fulfillment, scheduled fulfillment, vCenter migration, and the manual Reconfigure Resources command. This ensures that new and expanded disks are placed on a datastore with sufficient storage space. Once deployment or fulfillment has succeeded (or failed), the storage reservation is released.

Setting the datastore threshold

Access through:

Configuration menu > Self-Service > Placement tab

Available to:

Commander role of Superuser

To prevent over-utilization of datastores when a VM is being deployed, change the datastore threshold under Datastore Placement.

datastore-threshold

Set the threshold for datastore usage by entering a number in the text field. The default is 80%, meaning that deployment fails when it would cause the target datastore to be more than 80% full.

Deployment will fail only if all datastores assigned to the target storage tier would exceed this threshold. If you have configured email notification for all requests, emails are sent when all datastores assigned to a storage tier used in a deployment destination have exceeded this threshold.

Tip: Schedule a search for datastores that are approaching the configured threshold. Go to Tools > Search and select Datastores. Run the public search "Datastores with less than 20% free space". Click View Query, and adjust the parameters as required. Run the search and click Schedule. See Running and Scheduling Saved Searches.

To remove a threshold, enter 0.

Changing the datastore filling strategy

Access through:

Configuration menu > Self-Service > Placement tab

Available to:

Commander role of Superuser

datastore-placement

With the default setting, Choose datastore with the most free space, Commander deploys to the datastore with the most free space, up to the configured threshold.

If you need to change the default behavior in order to leave large amounts of free space available for large VMs, under Datastore Filling Strategy, select Leave largest block of free space available. With this option, Commander tries to fill up an available datastore before moving on to the next datastore.

With either option, the datastore must match the storage tier requested for disks, and all the VM's disks with the same tier must fit into the datastore, without exceeding the threshold.

Calculating disk size for placement

Access through:

Configuration menu > Self-Service > Provisioning tab > Global Provisioning Configuration

Available to:

Commander role of Superuser

calculate-disk-size

With the default setting, Actual space that deployed service will consume, Commander uses the current "used space" of the source template when calculating disk size for a thin-provisioned disk. For linked clones, Commander uses a disk size of 0. This setting allows you to provision VMs that significantly over-commit the datastore, so you should select this setting when you know that VMs are unlikely to grow to their full size.

If you instead want Commander to ignore the fact that the disk will be thin-provisioned, or that the VM will be a linked clone, select Full size of all configured disks. This setting allows placement to accommodate possible VM growth that may fill the disk.