vCenter downtime impact on Horizon 7.13

[nblr06]

I'm currently using vCenter 7 with Horizon 7.13.0 and planning for a vCenter server patch update task, therefore the VCSA won't be online for hours(estimated).

(The related components in this infrastructure  are basically the instant-clone desktop pools, unified access gateway, dynamic environment manager. No other complicated settings/nodes are applied/utilized, the desktop pools are the primary application.)

As far as i know, when the VCSA is offline the horizon will not be able to perform any provisioning/editing related tasks through vCenter, but I'm not so sure about whether the desktop pools' connection will be affected or not.

It seemed that the authentication/connection process between desktop pools and Horizon AD users always bypass vCenter.

Just hope the VCSA update process won't damage the current Horizon desktops and the user's connections.

Does anyone know the possible impact?

[Mickeybyte · Accepted solution]

@nblr06 

When vCenter is not available, users will still be able to login to Horizon VDI or RDSH pools. Just make sure you have enough provisioned machines because during the vCenter maintenance, no instant/linked clones will be created or removed. 

So if you expect that let's say new 200 users will logon during the vCenter maintenance, make sure you have 200 desktops available before you start the vCenter maintenance. 

Once vCenter is up and running again, it will handle the missed refresh operations of instant/linked clone desktops

[chriskoch99]

Late to the game here, maybe, but just remember that (if you're using it) App Volumes relies heavily on vCenter to do the work of attaching .vmdk appstacks to the VMs users are logging into.   So, while you can somewhat mitigate the impact on users from a purely Horizon standpoint, App Volumes impact can't be avoided.  The App Volumes vCenter work occurs during login and logoff events, but not really in between.