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Last updated: April 8, 2026

Quick Answer: Yes, vMotion can be used with virtual machines (VMs) that have snapshots, but with significant caveats and performance implications. While technically possible, vMotioning a VM with snapshots is generally discouraged for production environments due to the potential for extended downtime and performance degradation. The process involves migrating not only the VM's active state but also the delta disk(s) associated with the snapshot, which can be a large and complex operation.

Key Facts

vMotioning a VM with snapshots is possible but not recommended for production environments.
The vMotion process for snapshot VMs is slower and can cause extended downtime.
Snapshots introduce delta disks, which must be migrated along with the active VM state.
Best practice dictates consolidating or deleting snapshots before performing vMotion.
Cold migration (shutting down the VM) is often a more reliable alternative when snapshots are present.

Overview

The concept of virtual machine snapshots is a powerful tool for administrators, allowing them to capture the state of a virtual machine at a specific point in time. This is incredibly useful for testing software updates, applying patches, or making significant configuration changes, as it provides a quick rollback mechanism. However, when these snapshots are retained for extended periods, they can introduce complexities into routine virtual machine management operations, such as live migrations. The question of whether a virtual machine (VM) with existing snapshots can be vMotioned – VMware's technology for live migration – is a common one, and the answer is nuanced.

While vMotion is designed to provide seamless live migration of running VMs with minimal downtime, its behavior changes when snapshots are involved. Essentially, a snapshot represents a point-in-time copy of a VM's disk files (delta disks) and memory state. When a VM is vMotioned with snapshots, the migration process needs to account for these delta disks, which can significantly increase the complexity and duration of the migration. This can lead to performance issues and extended downtime, negating the primary benefits of vMotion in many scenarios.

How It Works

Snapshot Mechanism: When a snapshot is taken, the VM's original virtual disk file (VMDK) is locked, and a new delta disk file (also a VMDK) is created. All subsequent write operations are directed to this delta disk. This allows the original disk to remain unchanged, preserving the VM's state at the time the snapshot was taken. Subsequent snapshots create further delta disks, forming a chain.
vMotion Process: vMotion works by copying the VM's memory and disk state from the source host to the destination host while the VM remains running. This involves transferring the active memory pages and then the disk data. For VMs without snapshots, this is a relatively straightforward process.
vMotion with Snapshots: When a VM with snapshots is vMotioned, the system must also account for the delta disk(s). This means that the vMotion process needs to migrate not only the active memory and the current state of the delta disk but also potentially the entire chain of delta disks up to the active one. This significantly increases the amount of data that needs to be transferred and processed.
Performance Impact: Because of the additional data and complexity involved in migrating snapshot chains, vMotioning a VM with snapshots is typically much slower than vMotioning a VM without them. The process can also lead to increased I/O on the storage system and potentially higher CPU utilization on both the source and destination hosts. In some cases, the extended time required for the migration might even result in the VM becoming unresponsive or experiencing a brief period of downtime, defeating the purpose of live migration.

Key Comparisons

Feature	vMotion with Snapshots	vMotion without Snapshots
Migration Speed	Slower	Faster
Downtime Potential	Higher	Minimal to None
Complexity	High	Low
Storage I/O	Increased	Standard

Why It Matters

Production Stability: For mission-critical production VMs, the risk of extended downtime or performance degradation during a vMotion with snapshots is unacceptable. Administrators prioritize stability and availability, making it crucial to manage snapshots effectively before performing live migrations.
Resource Utilization: The increased resource demands of vMotioning snapshot VMs can impact the performance of other VMs running on the same hosts or storage. This can lead to a cascading effect of performance issues across the virtualized environment, affecting overall efficiency.
Best Practices: VMware's best practices consistently advise against running production VMs with numerous or long-lived snapshots. Consolidating or deleting snapshots before performing vMotion is a standard procedure to ensure smooth and efficient operations. If immediate migration is required and snapshots cannot be removed, a cold migration (shutting down the VM) might be a more reliable option, albeit with planned downtime.

In conclusion, while technically feasible, vMotioning a VM with snapshots introduces significant risks and operational challenges. The best approach is always to maintain a clean snapshot strategy, consolidating or removing snapshots before undertaking live migrations to ensure the seamless operation and stability of your virtualized environment. Ignoring this can lead to unexpected issues and compromises the core benefits of virtualization technologies like vMotion.