VMware HCX – Types of Migrations

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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

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