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HCX Migration Known Issues and Solution-Lessons Learnt !


Problem StatementReasonSolution
Failed to create the replica placeholder disks at the target site. Unable to create dummy disk at target siteTarget is having the folder with the same nameSearch the folder with VM name in datastore and delete before starting the replication
VM power off task status failed during VR migrationServer did not powered off during the cutoverSelect forced power off option before migrating the server
Failed to enable replication. Enable replication on HBR manager failedServer is having RDM or Source ESXi is not in healthy stateConvert RDM into VMDK or change the compatibility mode physical to virtual
Replication stuck at any pointDisk is added or removed during the replicationDo not do any hardware changes during replication
Fleet applaince is not found for the serverMigration service is not deployed for clusterIncluded that cluster in any existing migration service or deploy new CGW for that cluster
Cutover failed due to reserver MAC addressVM is having vCenter reserve MAC addressDo not select option ‘retain MAC address’
Table: HCX Migration Lessons Learnt

Dhiraj Dhall has more than 15 years of transformation delivery experience in cloud computing, infrastructure, dev-ops, microservices and container with larger global customers. He is a senior Architect and successfully delivered various kind of global project delivery such as greenfield, consolidation, SDDC and migration. 

Addressing Latency Issues in HCX-Network Extension !


Brief Summary:

When we configure Network extension in HCX to extend the L2 between Source and Target Datacentre, HCX deploy Network extension appliance in both Datacentres. Once successfully deployed, VLAN will be extended.

In HCX, when we migrate VM (using L2 extension) from Source to target Datacentre, VM will communicate back to source Datacentre for inter Datacentre VLAN, outside datacenter and other required communication because gateway still exist at source Datacentre.

Problem Statement:

The problem you may face If you have many network intensive virtual workloads (from one of particular VLAN) to migrate to target datacentre then Network extension could be a bottleneck and workloads may experience latency issue.

Solution Detail:

It is always better to migrate all one respective VLAN (Lets VLAN ID-10) as quickly as possible and cutover that VLAN to start routing the traffic from Target Datacentre instead of source. Due to unavoidable circumstances, if you are not in position to migrate all VMs in limited timeframe and even experiencing latency issue then you must plan to extend the VLAN through physical switches by using OTV or similar extension method.

Another factors to be considered:

  • Sufficient Migration link availability
  • At least 10 G network speed (VMNIC) for both Source and Target Hypervisors
Figure-1: HCX Layer-2 Extension

Dhiraj Dhall has more than 15 years of transformation delivery experience in cloud computing, infrastructure, dev-ops, microservices and container with larger global customers. He is a senior Architect and successfully delivered various kind of global project delivery such as greenfield, consolidation, SDDC and migration.