vCloud Director VM placement not balanced across multiple vSAN clusters in a PVDC
Article ID: 418042
Updated On:
Products
Issue/Introduction
In vCloud Director (vCD), a Provider VDC (PVDC) is configured to use datastores from multiple, independent vSAN clusters. A single VM storage policy is created that tags all vSAN datastores from all clusters. When deploying new virtual machines (VMs) or vApps, all new VMs are placed on the datastore of only one vSAN cluster, instead of being load-balanced across all available clusters.
Environment
10.x
Cause
This is the expected behavior. vSphere Storage DRS (SDRS) cannot be used for initial placement across independent vSAN datastores, as they cannot be combined into a vSphere Datastore Cluster.
When vCloud Director is presented with a single storage policy that makes multiple independent datastores compatible, its default placement engine does not automatically load-balance new deployments across them. It will typically select one datastore and continue to place VMs there until a capacity threshold is met.
Resolution
To control VM placement and manually distribute workloads across the different vSAN clusters, you must create separate storage policies for each vSAN datastore.
-
In vCenter, create a unique storage policy for each vSAN cluster's datastore (e.g.,
Policy-ClusterA,Policy-ClusterB). -
In vCloud Director, add these new storage policies to the Provider VDC (PVDC).
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When deploying a new VM or vApp, manually select the specific storage policy (e.g.,
Policy-ClusterB) that corresponds to the vSAN cluster datastore you wish to deploy to.
Additional Information
This method uses vCloud Director's Storage-Policy Based Management (SPBM) as the mechanism for manually directing VM placement.
Cloud Director Storage and Libraries (Telco Cloud Platform 5.0 Docs)
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