When you create, expand, extent, or delete a datastore, a rescan of your HBAs is automatically initiated. However, this rescan may result in a “rescan storm” when you are building a new environment and may result in issues such as packet drops and poor performance. In such cases, you may want to disable auto-rescan.
This article provides the steps to disable auto-rescan.
Note: Auto-rescan enables other hosts in the cluster to recognize and use a newly created datastore immediately. Disabling auto-rescan may create issues when the hosts are unable to recognize datastores. For example, during vMotion, the destination host may reject the request because it is unable to recognize the datastore created by the source host. VMware recommends you to disable auto-rescan only when building a new environment.