The way you approach this migration is a best one.
Install a new vCenter 6 on each datacenter. Divide your ESXi servers datacenter wise and add them to new vCenters. As you do not use any advanced features available in vCenter, Its good to install a new vCenter and add the ESXi servers on them, instead of upgrading the existing vCenters.
Refer VMware vSphere 6.0 Release Notes, if you face any issues during/after installing vCenter 6. There are so many "Known issues" explained here.
Do you have any specific reason to install external PSC? If not, Think about installing embedded PSC. Refer: vSphere 6.0 Documentation Center for pros and cons of PSC models.
VMware state that two embedded vCenter+PCS servers is deprecated.... see here VMware KB: List of recommended topologies for VMware vSphere 6.0.x
However, that same document doesn't explore the two-VC+two+PCS without a LB either. . I really don't want to put a virtual LB hosted in the same VMware environment in which it is protecting PCS for. But I can from document http://www.vmware.com/files/pdf/techpaper/VMware-vCenter-Server6-Availability-Guide.pdf (page 14) that it is supported.
"Multisite vCenter Server and PSC Basic Architecture
In this configuration, each site is independent, with PSC replication between sites. The vCenter Server system detects site topologies and uses the local PSC under normal circumstances. Users can seamlessly move the vCenter Server systems between PSCs when necessary "
Just a thought, Why don't I use virtual appliance, will be eliminating need of OS license anyway. As it comes with SUSE enterprise linux version 11.
and it supports all the deployment topology that I want.
Why don't you just have 2 x EPSC in a single SSO domain, but each in its individual site. That means that if you want to migrate to a Load balanced environment you can at a later time.
Also gives you seperation geographically.
We have MS Datacenter licensing on each ESX host anyway, so we don't really pay for additional Windows licenses.
I'm still preferring the 2EPCS model because it gives me a bit more resiliency and I can't really identify a disadvantage.
If you have 2 sites, I'm not sure you d get extra resiliency, as with one EPSC down the site would effectively be down, but the only way to resolve that is to use a load balancer.
Just to explain a little more, you point the vcenter to a specific address which is the EPSC, the only way to make the redundant is to use a Load balanced address. You could have 2 x EPSC in each site and change the pointer if it fails in vcenter, but its not exactly quick.
You can apparently move a vcenter to the other PCS easily...
"Users can seamlessly move the vCenter Server systems between PSCs when necessary " - http://www.vmware.com/files/pdf/techpaper/VMware-vCenter-Server6-Availability-Guide.pdf page 14
With a single PCS you would need a rebuild/restore.
I agree a LB is "better" technologically, but I just don't like to idea of a Netscaler VPX in front of my PCSs.
VMware should have the LB capability built-in!
yer that's possible, as I mentioned above it's just not that quick, and requires intervention that's all.
i have a physical netscaler In front of mine and it's set as a failover vip rather than load balanced.
I am also contemplating how our design scenario would look as well.
For simplicity sake, say we have 3 locations and 9 vCenter VMS. Test/Dev/Prod in each location. Currently we are in linked mode with a single SSO domain and external DBs for each vCenter VM.
I would install an external PSC (3 total) 1 in each location. Then install the applicable vCenter VMS in those 3 locations as well. My question is can that be done without any load balancing methods? IE: Can I have multiple external PSCs with no LB? I read though the documentation but it almost states you need to LB. We do have some load balancing appliances - but they are getting replaced soon and want to simplify my design.
Any clarification would be appreciated.
Would it be better to have PSC external. Maybe for flexibility and migration in the future. I heard if psc and vcenter is on one box, you cannot migrate psc off of it later and need a complete reinstall
Having PSC deployment as external to your vCenter management node is certainly better for a scenario where you are looking at scaling out your infrastructure in future.
you are right, embedded deployment will trouble you if you want to take PSC off that node and make it external.
Is there any migration way to the new vCenter 6 without virtual machine downtime ?
Is the only way to disconnect each Host from the source vCenter and reconnected to the destination vCetner?