Multiple vMotion (Migrate virtual machine) tasks stuck at 12% with the detail: “Resources currently in use by other operations. Waiting.”

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

• Multiple vMotion tasks are stuck at 12% with the detail: "Resources currently in use by other operations. Waiting." This prevents virtual machine migrations from completing.
• Nearly 8 concurrent vMotion tasks were initiated by DRS, and when the customer attempted a manual vMotion during this activity, that specific task paused at 12% completion.

Environment

• vCenter 8.x
• vCenter 9.x
• ESXi 8.x
• ESX 9.x

Cause

• This occurs because vSphere limits the number of concurrent migration operations to prevent resource exhaustion on ESXi hosts.
• Exceeding these limits will cause subsequent tasks to queue and wait indefinitely until sufficient resources become available from completing operations.

Resolution

This is expected behavior, all ESXi hosts are subject to a maximum concurrent migration cost of 8—a limit shared by vMotion, Storage vMotion, and provisioning activities (cloning, deployment, cold migration)—meaning a host can, for example, only support two Storage vMotions or a mix of one Storage vMotion and four vMotions simultaneously.

Additional Information

vCenter Limits on Simultaneous Migrations - vSphere 8

vCenter Limits on Simultaneous Migrations - vSphere 9

Resource Manager Settings for Managing Migrations

vCenter Limits for Concurrent vMotion