Understanding HCX Bulk Migration
- Mohammed Bilal
- Jul 14
- 3 min read
This migration method uses the VMware vSphere Replication protocols to move the virtual machines to a destination site.
HCX Bulk Migration provides the following benefits:
The Bulk migration option is designed for moving virtual machines in parallel.
This migration type can be set to complete on a pre-defined schedule.
The virtual machine runs at the source site until the failover begins. The service interruption with the bulk migration is equivalent to a reboot.
A Bulk Migration request triggers the following actions:
Replication begins an initial full synchronization transfer to the remote site. The time it takes to replicate is a function of the size of the VM, the data change rate on the virtual machine disk files (VMDKs), and available bandwidth.
Replication bandwidth consumption varies depending on the number of disks for each VM and the number of VMs being migrated concurrently.
The switchover can start immediately after the initial synchronization is completed, or it can be delayed until a specific time using the scheduled migration option. By using the scheduled migration option, the switchover can occur during a maintenance window.
A delta synchronization with two-hour recovery point objective (RPO) occurs while waiting for the scheduled switchover, after the initial synchronization is completed.
Depending upon data churn on source disk, additional snapshots are being created during the RPO cycle. After each RPO cycle, disk consolidation takes place and creates a “hbrdisk.RDID vmdk” called as replica instance vmdk file on target datastore. Refer VMware KB 87028.
During switchover, the source VM is powered off to perform a final off-line synchronization, data consolidation, and VM instantiation at the target data center.
Following the switchover, the migrated VM replica is powered on and
HCX Manager
renames the original VM using a POSIX timestamp suffix to avoid a naming conflict with the migrated VM. If the
Retain MAC
option was not selected, the migrated VM obtains a new MAC address.
The migration completes and the original VM is copied to the Migrated VMs folder.
Bulk Migration Requirements and Restrictions; you can refer to this VMware document.
Procedure:
Navigate to the HCX dashboard.
Select the Services > Migration.
The Migrate Tracking window displays a summary of virtual machine migrations.
Select Migrate Virtual Machines.
Select the Remote Site Connection.
From the Migration Profile, select Bulk Migration
The list of virtual machines available for migration appears in the display.
Select the virtual machines you want to migrate.
Set the Transfer and Placement, Switchover, Interconnect Service Mesh, and Extended options.
To apply default settings for all selected virtual machines, use the green area of the interface at the top of the window.
To set machine-specific Transfer, Placement, Interconnect Service Mesh, and Switchover options, select a specific virtual machine and expand the entry.
Reveiw the information and click Validation to check in case there are any issues in the configuration before you click GO
Once you click on Go, the migration is initiated:
You can monitor the migration status from the same Migration page:
Below are the different stages during the migration process, where the first Migration is initiated
Next, Transfer sync starts
Next, the switchover is started
Finally, the migration is completed, andthe same process starts for the remaining VMs
Also, the migration tasks can be monitored from vCenter:
You can also track the Events for the migration by expanding the VM from the same migration page and click on the show previous events to check on the list of events steps by step to understand the migration process:
Note:
You can schedule the migration date and time for Bulk, RAV, and OSAM migrations as part of the Switchover settings. Scheduling vMotion migrations is not available.
If the VM is powered off, Cold Migration is set by default.