Migrating to new Hosts with separate datacenters and VCSA

[danstr1]

I'm in the midst of migrating my existing VM's to a new infrastructure. I have some questions on migrating the VM's from the old to new. The environment is small with only two hosts (see below for more info). I have two new servers to serve as replacements for my aging hardware. Below I've included relevant details of my old and new virtual infrastructures.

Existing:

- Two Hosts running 4 VM's each. The hosts are Dell R610's.

- The environment is VMWare vSphere 6.5 with its own, separate VCSA

- Storage is shared via Direct Attached Storage (DAS) with a Dell MD3220 SAN. These are directly attached via an HBA interface to each host which currently offers HA. All VM's are stored on the shared storage. There are no VM's on the local storage nor are they adequately sized to do so.

New:

- Two Hosts running a VMWare based hyperconverged solution. This provides the shared storage and redundancy etc with the need for a SAN.

- This is a hyperconverged solution by Dell that required the ProDeploy services. Given that, the new environment is setup correctly and ready to go (thankfully, not my doing!). The servers are VSAN ready Dell EMC R640's Ready Nodes

- The environment is all vSphere 6.7 U2 with its own VCSA server and datacenter

Question:

As you can see by the details above, the new and old environment are entirely separate entities. This is where the complications begin (in my mind). I've read several various articles and past support cases on the topic and think I have an approach narrowed down. The plan is to disconnect and remove the hosts from the existing VCSA in the old environment. AFterwards, the old hosts will then be connected to the new environment via the new VCSA residing on it. This will allow me to use vMotion (verified my licensing should allow) to migrate the VM's from the old hosts to the new. Sounds way too simple which has me concerned..... My question is, since the VM's in the old environment are stored on the SAN, is the new enviroment/VCSA going to be able to recognize them? Or, because I have them direct attached, does the host recognize this as local storage which will translate to the new VCSA and hosts? Also, once I disconnect/remove the Hosts from the original VCSA, am I able to easily reconnect it to the old without ramification if things go awry in the new environment ( a back out plan....).

Thanks for reading and any suggestions! - Dan

[VysakhNair · Accepted solution]

danstr1​

As your old and new infrastructure does not have a shared storage , you can add old ESXi 6.5 hosts to new VCSA 6.7.

A suggested, you have to power off the VMs and do a cold vMotion (Bcz there is not common storage) - Downtime time will be more compared to size of the VM.

Before removing from old vCenter please consider, if you are using VMware Distributed switch please migrate to Slandered switch( Else if you may face some network challenges)

Make sure same network is available in new hosts so you can connect to respective networks after cold vMotion

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[danstr1]

Hi VysakhNair! Thanks for your response. Sounds like I should be able to achieve this but I need to anticipate downtown by the VM's as they are cold vMotioned to the new storage. I verified that I only have standard switches in my environment (no distributed) and I can also confirm that the VM's will be on the same network before and after the migration.

While doing this, am I able to disconnect/remove the original host from the old vSphere with just 1 VM running on it. Then connect to the new vSphere where I can attempt the vMotion. After doing so, can I still disconnect the original host from the new environment and connect it back to the old vSphere environment without issue? The reason I ask is that by doing so this would allow me to do some initial testing and gradually migrate my VM's to the new environment. Basically, I'd vMotion a few more VM's to the old host each time.

[VysakhNair]

danstr1​

Yes you can do that.

Disconnect from old vCenter add to new vCenter and after cold vMotion again move the ESXi host to old vCenter

[danstr1]

What would the proper procedure for disconnecting/removing the Host from vSphere be? Would I proceed by simply selecting the host and disconnect then connect it to the new host? Or, do I need to disconnect and Remove from inventory afterwards? I also see the option to Disassociate host.

[VysakhNair]

If no VMs are running under that host you can put host in Maintenance mode and remove from old vCenter and add it on new vCenter

[danstr1]

What are the options if VM's are running or is that simply not an option in this case? The proper procedure would then be to shutdown VM's => place Host in maintenance mode => Remove?

[VysakhNair]

danstr1​

If VM is running you can directly disconnect from old vCenter and add to new vCenter,

[danstr1]

Thanks so much for your help VysakhNair!