VMware HCX – Types of Migrations

Leverage the cheat sheet below whenever you are considering moving workloads with HCX so you can always pick the best strategy and reduce the downtime!

• Cold migration
  • Default migration type for VMs that are powered off.
  • Leverages NFC (Network File Copy) protocol.
  • MAC and IP addresses are both preserved.
  • Single threaded operation, one VM migrated at a time.

Requirements:

• Virtual Hardware version must be 9 or higher.
• 100Mbps of throughput (or higher) is required.

Restrictions:

• Shared VMDK Files
• Attached virtual media (floppy images, ISOs)

• Bulk Migration
  • Reduces downtime by leveraging vSphere replication while the VM remains online.
  • After the full sync finishes, one delta sync will occur.
  • Once the delta sync is completed, switchover will begin by shutting down the VM at the source site and powering it on at the destination site.
  • HCX will add a timestamp suffix to the migrated VM to avoid name conflicts.
  • MAC address will remain the same if the “Retain MAC” option is selected.

Requirements:

• Virtual Hardware version 7 or higher
• VMware Tools need to be installed on the VM

Restrictions:

• Physical RDMs not supported.
• Attached virtual media (floppy images, ISOs)
• Directpath path devices need to be removed prior to migration.
• VMs with snapshots can be migrated, but snapshots will be removed during migration.
• VMs with SCSI bus sharing cannot be migrated.
• New disk UUIDs are generated after migrated.
• vNVME controllers are not supported.
• NSX security tags will NOT be migrated, vSphere tags will migrate if vCenter is 6.0+

• Bulk Migration with OS assisted replication:
  • This type of migration is targeted for non vSphere VMs (KVM and Hyper-V)
  • Sentinel agent gathers system information and assist with data replication.
  • HCX builds the inventory of VMs as the software is installed on the guest OS.
  • Full synchronization happens in the background while the VM remains online.
  • Delta synchronizations continue to happen after the full sync is completed.
  • During switchover, source VM shuts off and replicated VM powers on
  • VM is not modified since the VM was in a non vSphere environment before.
  • VMware tools is automatically installed during the first boot.

Requirements:

• HCX Sentinel agent software is required
• Windows or Linux OS

Restrictions for Windows VMs:

• Windows 2008 SP2 (32/64 bit) or higher is required.
• Cannot sync logical volumes.
• Dynamic disks are not supported.
• NTFS format required for volumes.
• VSS snapshots will not be migrated.
• VLAN interfaces are not supported.
• Failover cluster nodes are not supported.
• Guest OS needs to have 64 volumes or less.

Restrictions for Linux VMs:

• Supported file systems include: ext2, ext3, ext4, XFS
• Software RAID not supported.
• Encrypted file systems not supported.
• Static routes are not supported.
• VLAN interfaces are not supported.
• Removable media on /etc/fstab are not supported (comment out before migration).

• HCX vMotion
  • Default live migration type for a single VM.
  • vMotion transfers disk datal and active memory/execution state.
  • MAC and IP addresses are both preserved.
  • Single threaded operation, one VM migrated at a time.

Requirements:

• Virtual Hardware version must be 9 or higher.
• 100Mbps of throughput (or higher) is required.

Restrictions:

• Shared VMDK Files
• Attached virtual media (floppy images, ISOs)

• HCX vMotion > Bulk Migration with Replication Assisted vMotion (RAV):
  • RAV leverages both vSphere replication and vMotion services
  • Zero downtime required
  • Multiple VMs are replicated simultaneously, followed by continuous delta syncs.
  • During the switchover phase, one VM gets migrated at a time (serial operation)
  • HCX will remove the source VM and connect it to the network at the destination.
  • NFC service is used as a secondary protocol on this type of migration.

Requirements:

• Virtual Hardware version must be 9 or higher.
• 100Mbps of throughput (or higher) is required.
• Resources to power on and use the VM must be available at the destination site.

Restrictions:

• Shared VMDK Files
• Attached virtual media (floppy images, ISOs)
• VMs with independent persistent/non-persistent disks are not supported.
• VMDK disks over 2TB are not supported
• VMs with snapshots cannot be migrated
• Physical RDMs not supported.
• Attached virtual media (floppy images, ISOs)
• Directpath path devices need to be removed prior to migration.
• VMs with SCSI bus sharing cannot be migrated.
• New disk UUIDs are generated after migrated.
• vNVME controllers are not supported.

Hope this guide is helpful with your journey to the cloud!

PS: Do you know what HCX stands for? Just in case, it stands for Hybrid Cloud Extension