Quick Resume & Stun During Page Send

Since the amount of memory available to virtual machines is always growing, VMware must be aware of this and must optimize vMotion for these VMs. Therefore VMware introduced some VMware vMotion Special Features to cover the future needs. Quick Resume is a minimal modification to the vMotion procedure, since the entire memory capacity on the target host is not required until the migration is finished completely. Quick Resume activates the target VM already before the entire memory data has been migrated. The source VM is paused (Stun Mode), but its resources are not freed. In the background, VMware continues to copy the rest of the memory content and allows the target ESX host to access pages on the source ESX host.

As beautiful as this process seems at first glance, it also introduces the possibility of dangerous issues in the case of a hardware crash during the Quick Resume process. In order to circumvent this, VMware uses a file on the central storage that acts as a sort of data buffer so that in the case of a hardware failure the migration process can still be completed. Of course this leads to this form of Quick Resume having a decreased performance, but without this functionality a vMotion process between VMs with a large amount of vRAM would not be possible.

In vSphere 5.x this functionality is controlled using Stun During Page Send or Slow Down During Page Send (SDPS). Using this functionality the vMotion process monitors the rate of changed memory pages (dirty pages) during the vMotion procedure and compares this with the current possible transfer bandwidth to the target ESX. Based on this result, the CPU of the source VM can be slowed somewhat by artificially introducing stops (sleep) on the order of milliseconds to slow down the rate of change. Doing this gives the vMotion process the chance to migrate even very dynamic systems.

Though this may introduce performance degradations, one must consider that slow data transfer rates or high data modification rates previously led to regular vMotion failures in older vMotion versions. 

Multi-NIC vMotion Support

Multi-NIC vMotion support, available since vSphere 5.x, is a clear step forward. It increases the bandwidth of the vMotion transfer by allowing multiple network adapters to be used simultaneously. However in order to benefit from the multi-NIC support there are some design considerations to take into account regarding the network infrastructure in the vSphere environment. 

It is possible to couple up to 4 1-Gbe and 16 10-Gbe network cards together for the vMotion transfer when mixing speed. The full list can be found here: VMware vSphere 6 Configuration Maximums

VMware vMotion Special Features - VMware vSphere 6 configuration maximum

You should pay attention during the planning stage to which virtual machines will be used (vRAM configuration) as well as the layout of the server systems (PCI bus use) in order to properly handle increased network traffic (peaks).

Higher Latency Link Support

Before vSphere 5.x latencies above 5 ms were not permitted, despite such latencies being not uncommon when using vMotion over long distances (Long Distance vMotion). For this reason some cluster implementations spanning the borders of computing centers could not be operated or could  only be operated in a limited manner. To alleviate this limitation the supported latency was doubled from 5 ms to 10 ms in vSphere 5.5, but vSphere 6.0 shows up with 150ms support, however this feature requires an Enterprise Plus license.

Cross VMware vCenter Support

You can move between vCenter Servers with all migration types, cold  migrate, vMotion and Storage vMotion. There is also a way of a shared nothing migration, if you don’t have any shared storage accessible by Source and Target ESXi host!

VMware vMotion monitoring

The knowledge about these VMware vMotion Special Features as well as the knowledge how to use them go hand in hand.

To get a good feeling about your daily vMotion tasks and how long they take, check out our 

VMotion/svMotion Report

Metrics and Logs

(formerly, Opvizor Performance Analyzer)

VMware vSphere & Cloud

Monitor and Analyze Performance and Log files:
Performance monitoring for your systems and applications with log analysis (tamperproof using immudb) and license compliance (RedHat, Oracle, SAP and more) in one virtual appliance!

Subscribe to Our Newsletter

Get the latest product updates, company news, and special offers delivered right to your inbox.

Subscribe to our newsletter

Use Case - Tamper-resistant Clinical Trials


Blockchain PoCs were unsuccessful due to complexity and lack of developers.

Still the goal of data immutability as well as client verification is a crucial. Furthermore, the system needs to be easy to use and operate (allowing backup, maintenance windows aso.).


immudb is running in different datacenters across the globe. All clinical trial information is stored in immudb either as transactions or the pdf documents as a whole.

Having that single source of truth with versioned, timestamped, and cryptographically verifiable records, enables a whole new way of transparency and trust.

Use Case - Finance


Store the source data, the decision and the rule base for financial support from governments timestamped, verifiable.

A very important functionality is the ability to compare the historic decision (based on the past rulebase) with the rulebase at a different date. Fully cryptographic verifiable Time Travel queries are required to be able to achieve that comparison.


While the source data, rulebase and the documented decision are stored in verifiable Blobs in immudb, the transaction is stored using the relational layer of immudb.

That allows the use of immudb’s time travel capabilities to retrieve verified historic data and recalculate with the most recent rulebase.

Use Case - eCommerce and NFT marketplace


No matter if it’s an eCommerce platform or NFT marketplace, the goals are similar:

  • High amount of transactions (potentially millions a second)
  • Ability to read and write multiple records within one transaction
  • prevent overwrite or updates on transactions
  • comply with regulations (PCI, GDPR, …)


immudb is typically scaled out using Hyperscaler (i. e. AWS, Google Cloud, Microsoft Azure) distributed across the Globe. Auditors are also distributed to track the verification proof over time. Additionally, the shop or marketplace applications store immudb cryptographic state information. That high level of integrity and tamper-evidence while maintaining a very high transaction speed is key for companies to chose immudb.

Use Case - IoT Sensor Data


IoT sensor data received by devices collecting environment data needs to be stored locally in a cryptographically verifiable manner until the data is transferred to a central datacenter. The data integrity needs to be verifiable at any given point in time and while in transit.


immudb runs embedded on the IoT device itself and is consistently audited by external probes. The data transfer to audit is minimal and works even with minimum bandwidth and unreliable connections.

Whenever the IoT devices are connected to a high bandwidth, the data transfer happens to a data center (large immudb deployment) and the source and destination date integrity is fully verified.

Use Case - DevOps Evidence


CI/CD and application build logs need to be stored auditable and tamper-evident.
A very high Performance is required as the system should not slow down any build process.
Scalability is key as billions of artifacts are expected within the next years.
Next to a possibility of integrity validation, data needs to be retrievable by pipeline job id or digital asset checksum.


As part of the CI/CD audit functionality, data is stored within immudb using the Key/Value functionality. Key is either the CI/CD job id (i. e. Jenkins or GitLab) or the checksum of the resulting build or container image.

White Paper — Registration

We will also send you the research paper
via email.

CodeNotary — Webinar

White Paper — Registration

Please let us know where we can send the whitepaper on CodeNotary Trusted Software Supply Chain. 

Become a partner

Start Your Trial

Please enter contact information to receive an email with the virtual appliance download instructions.

Start Free Trial

Please enter contact information to receive an email with the free trial details.