vCenter 6.5 PSC multisite vs single site advantages

[HariRajan]

I have few questions regarding Multisite replication of PSC in vSphere 6.5 , can you please help me to sort it out.

1. 1) What is the advantages of multi-site psc deployment in vSphere 6.5 , reason why I am asking this is , in vSphere 6.5 if one of the PSC fails in a site , we cannot register the vCenter to another PSC which is in another site (forget about multiple psc in a single site now), we must register to another PSC in the same site even though rest of the PSC’s are in single SSO domain. This was supported in vSphere 6.0. Also if I have a multi-site deployment whether the PSC will do a cross-site replication?
2. 2) What is the advantages seeing in this multisite deployment vs single site ? (actually it is two physical site and configuring the psc as single site as mentioned in the below picture).

Multiple PSC site

Single PSC site

I am trying to understand what are the design considerations for single site deployment vs multi site , thanking in advance

Single PSC site

[activecloud]

Looking at the diagrams that you have posted, I am assuming these things

Physical site 1

     2 Venters

     2 PSCs

     Each vCenter is pointing to single PSC in the same physical site

Same for the other physical site.

Now if you are going to have 2 PSCs in the same physical site, then I do not see any risk as if one of the PSCs goes down, you can point to another PSC in the same physical site.

Also, this is now supported in vSphere 6.7 and you can now repoint your vCenter to a PSC at another vsphere site.

Giving 2 separate physical sites, same name for the vsphere site is not something I have ever seen or tested before. I am sure there must be a latency threshold with the PSCs for a single site, and doing this might violate that threshold.

Another option you can do is to have backups taken of the PSC appliances, which is a native feature with 6.5, and in case of a PSC failure, you can quickly deploy a new PSC, join in the same domain and restore from this backup.

I hope this helps.

[peetz · Accepted solution]

Hi Hari,

having multiple SSO sites is a concept that never really took off, because it doesn't have any benefits, but unnecessarily complicates the architecture, failure scenarios and troubleshooting.

This is why VMware declared this feature deprecated in the newly released vSphere 6.7. Future vSphere versions will no longer allow choosing an SSO site (see e.g. Upgrade Considerations for VMware vSphere 6.7 - VMware vSphere Blog ).

So I highly recommend using only one SSO site per SSO domain today already.

- Andreas

[HariRajan]

I really agree with your comments as there is no point in multi-site deployment , I have checked with VMware on the same and they are still saying upto 100 milliseconds latency is only supported (can go upto 150 milli seconds unofficially ). between the psc's if it is single site or multi-site . I am also seeing with multi site, we are not  getting any value rather it's an unnecessary complication . I really appreciate if anybody have any better insight on this thread and pls feel  free to comment it here.

[daphnissov]

SSO site names are/were nothing more than convenient labels for grouping. They were only logical constructs and not physical barriers within an SSO scope. As pointed out, that concept no longer exists which should simplify how design is thought about going forward.