What’s New in HCX 4.2 (Part 1 of 2)

HCX 4.2 is generally available! I’m going to highlight some of the new stuff in my own words.

I don’t know if others also experience cache issues, but you can navigate directly to the relevant docs here:

HCX 4.2 Release Notes

HCX 4.2 User Guide

HCX 4.2 Announcement blog

Migration Metrics, Estimates & Machine Learning

This has been an exciting theme for the HCX 4 releases. We’ve been adding functionality powered by migration data. HCX has been enabled to collect metrics relevant to vMotion and Replication from ongoing migrations starting with the 4.0 release.

Real-time Estimates use key metrics to provide a running estimate for an ongoing migration operations. This takes into account various factors like the virtual machine disk count, disk size activity, checksum, transfer capability of the IX, vmotion and replication concurrency, etc (~ 20 distinct metrics are available for these calculations).

Predictive Estimates are generated using a Machine Learning service on the HCX Systems that is fueled by historical migrations. The model is improved over time. The predictive estimates functionality can be invoked from the Migration Management interface on migration drafts.

Real-time estimates for HCX vMotion and Replication-Assisted vMotion migrations are now available (along with RT-estimates for Bulk).

To use the estimates features, the site paired HCX systems must be fully upgraded to version 4.2; an inconspicuous little clock along with the estimated time to completion is displayed in the progress column of an ongoing migration.

We understand that reporting progress as a percentage relative to the virtual machine and performance characteristics of the operation, and is not always intuitive. The HCX team is excited to provide a friendlier measure of progress for all of our most used migration types.

migration progress with time-based estimates

Predictive Estimates for Replication-Assisted vMotion are also possible now (along with Predictive Estimates for Bulk). For the initial release, predictive estimates are based on the replication portion of a RAV migration. Migration predictions are generated for the virtual machines in a mobility group (in the Migration Management interface.

To generate predictions – the site paired systems need to be running HCX 4.2 and the migration must be entered in HCX in a draft state. Drafts can be created with the HCX Enterprise Mobility Groups feature.

VM Metadata Migration

In HCX 4.0, the HCX vMotion migrations can carry over VM Custom Attributes; in 4.2 the functionality is expanded to HCX Bulk Migration, Cold Migration and Replication Assisted vMotion.

The option is selectable in the Extended Options. (Virtual Machine tags are always migrated)


That’s it for Part 1! In Part II (early next week) I will cover these topics:

  • OS Assisted Migration for VMware Cloud on AWS and VMC.
  • Integration with Cloud Director .
  • Updates “Network Underlay Requirements” this is one of my favorite things.


Thanks for reading! Please stay tuned!



🖐🏼 ✊🏼 ✌🏼 🤏🏼 🖖🏼

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