VMware Cloud Community
Gregm64
Contributor
Contributor

vCenter Server Std. on Site to Site Replication?

I will have two sites both sites are identical (2 Host with a SAN), the 1st site is the production site & the 2nd site is for replicating to it (Site to Site Replication), the sites will have different IP addresses of course. What I can't seem to get is a definite answer on is if I need to have vCenter Server Std. on both sites. I have vCenter Server on the production site but not sure about the replication site any in site on this would be great.

8 Replies
scott28tt
VMware Employee
VMware Employee

How else would you manage the hosts at the DR site otherwise?

What do you think the alternative is to running vCenter Server at that site?

If you’re asking because it won’t be an active unless you lose your primary site, all hosts and vCenter Servers need to be licensed.


-------------------------------------------------------------------------------------------------------------------------------------------------------------

Although I am a VMware employee I contribute to VMware Communities voluntarily (ie. not in any official capacity)
VMware Training & Certification blog
Gregm64
Contributor
Contributor

Thank you for your response.

Well, I thought it would need the vCenter Server License at the replication site but I was told different from the VMware support @ Dell. I was told that since I have vCenter Server on the Production site Host & it can see the replication site I didn't need to purchase another vCenter Server License since the vCenter Server License Per Instance can manage up to 1000 host.

Reply
0 Kudos
daphnissov
Immortal
Immortal

Bottom line is you ​must​ have vCenter at both sites. This means not only two separate instances (replicating the Prod version doesn't cut it) but also separate licenses, or at least two entitlements covered by the same license. So from a licensing perspective, this is either two distinct keys where each key is a single entitlement, or the same key enabling two instances. But from a bits perspective, each site much have its own distinct vCenter which manages the resources at that site.

bbalido9
Contributor
Contributor

Hi,

if you just want to replicate Vms between Production site to Replication site then you require only 1 Vcenter Server managing both sites just a 2 Datancenter within same vcenter.

Here Vsphere replication allows to replicate vms between 2 physical sites/ 2 datacenters and be able to recover Vms if esxi host or SAN goes Down in Production Site.

PS: the only concern here is that this operation or deployement involves some manual operation such as: VM Ip Customisation since both sites ISP is different or might be Layer3 in both sites; Unlike cross site network with layer2 for VM IP address.

Additionally, here you will require to manually prioritise your VMs recovery regarding which priority or sequence you want to recover those Vms.

-----

Alternatively if you are thinking of a seemless or full automation involving SAN/Block level replication with full VM Automated recovery process then you will require to have 1 Vcenter deployed in each Production and Replication where you will establish replication betwen the 2 sites.

Additionally you will require to deploy Vmware Site Recovery for the replication and recovery automation process which will perform complete recovery including VM ipcustomisation and Priority recovery.

--------

So please check what's your requirement or objective cause this will decide whether you can attain your objective with 1 Vcenter managing both site or deploy 1 Vcenter in each site with Full automation.

Hope this resolves your query.

daphnissov
Immortal
Immortal

I don't fully agree with your advice here, bbalido9​. Having discrete vCenters isn't just when requiring/desiring "full automation" but a necessity to fully safeguard the first site.

In your first example where you say

if you just want to replicate Vms between Production site to Replication site then you require only 1 Vcenter Server managing both sites just a 2 Datancenter within same vcenter.

Here Vsphere replication allows to replicate vms between 2 physical sites/ 2 datacenters and be able to recover Vms if esxi host or SAN goes Down in Production Site.

What happens if the storage array in the production site goes down completely or there's an earthquake that renders that site inoperable, and that site contained the one and only vCenter that managed both sites? How are you going to bring anything up let alone manage it? You can't, because you're screwed.

Although it's true that one vCenter can manage multiple hosts at multiple sites organized into logical data center objects, this is not sufficient for a DR topology or use case.

Even if you don't want "full automation" that involves orchestrated bring-up, recovery plans, etc., you still need failure domain isolation. You can't have pieces of infrastructure, whether they be control plane or data plane objects, live at one site only and expect to be able to operate correctly in an outage situation.

Reply
0 Kudos
bbalido9
Contributor
Contributor

Hi,

Assuming that your production sites go down completely, then as clarified before you will require manual operation to brings the replicated Vms at the Replicated sites.

If you are using San Replication the Datastore can be manually perfom SAN failover at the Replicated sites,  then access the datastore and register the Vms quickly.

If you are using vsphere replication then it's just a matter of browsing the datastore at the replication site and register the Vms to bring production online.

Ps: registering vm and powering on can be partly automated with either script on ssh host or powercli.

Additionally here Vcenter is not a priority since as mention there is only 2 host in this infrastructure.

Furthermore for Domain controllers, since there is 2 physical sites, its logical thinking that you will have either physical or virtual domain controllers and DNS server present at both sites for servers to connect to AD and for Users authentication based on the 2 Physical datacenter requirement with ISP.

-----

Again here solution is based on One's requirement, whether is Infrastructure management or Financial cost.

Every solution is customised according to your owns needs or requirement.

Reply
0 Kudos
daphnissov
Immortal
Immortal

Assuming that your production sites go down completely, then as clarified before you will require manual operation to brings the replicated Vms at the Replicated sites.

If you are using San Replication the Datastore can be manually perfom SAN failover at the Replicated sites,  then access the datastore and register the Vms quickly.

If you are using vsphere replication then it's just a matter of browsing the datastore at the replication site and register the Vms to bring production online.

Right, I understand all of this, but the fact remains you now have no management capabilities at that second site. What if you now need to monitor those failed over workloads? What if you now need to protect data locally until the primary site recovers? What if you have audit needs that still need to be fulfilled? Not having your management plane available may be acceptable if you don't care about those things, but that shouldn't be the general advice given to others. Can I sell you a car without a reverse gear? Drives perfectly straight so long as you never want to back up. Maybe you don't care and/or need one. Do you think it's wise to position a car to most of the general public that doesn't have a reverse gear? Certainly not.

Additionally here Vcenter is not a priority since as mention there is only 2 host in this infrastructure.

Furthermore for Domain controllers, since there is 2 physical sites, its logical thinking that you will have either physical or virtual domain controllers and DNS server present at both sites for servers to connect to AD and for Users authentication based on the 2 Physical datacenter requirement with ISP.

You're talking about your own personal usage in this instance, which I don't believe either reflects most customers' needs. Agree that it's commonplace to see applications like AD and DNS spanned across sites as these are applications which allow for native replication, but vCenter is a management component and not like either in that regard.

So, to summarize:

  • It is possible to have one vCenter manage multiple sites, but be aware of what you're getting.
  • The "standard" approach to DR is to have full capabilities at both sites, and that includes management portals.
  • Licensing needs to account for this level of redundancy.
Reply
0 Kudos
sjesse
Leadership
Leadership

I agree with this, and I originally looked at trying to use one vcenter, it all looks fine until you actually need to restore then it doesn't always work. If anyone goes this route do a real DR test and make sure vcenter is off and you can reliably do restores before you rely on it. There is a difference on saving money by not getting a product like SRM and cutting corners too much to reliably protect you work loads.The amount of time you spend getting it work in labor is probably more than the vcenter license costs.