Can someone please suggest that in a scaled Sitecore 9 environment for some reason if the Roles other than CM and CD are down, how the Websites will be impacted?
If the xConnect, Marketing Automation, xDb Reference Data Roles are down, will the CM and CD roles will be down as well or we have any configuration to avoid such dependency?
With xConnect off, the website will keep working BUT if you have any xConnect/Tracker code that is not null checked, it will fail.
Sitecore.Tracker?.Current?......
or
if(Tracker.Current?.IsActive == true)
{
// do stuff
}
All of the Analytics related actions in Sitecore forms will cause the forms to stop working. And action that happens after the failing analytics action will not run.
For Marketing Automation, Processing Engine and xConnect Search Indexer are just services and run out of channel from the website. None of the MA will run and any xConnect searching will be out of date.
The question: What happens to the experience if xConnect is down?
The Content Delivery Role uses the SessionEnd of the HTTP Request lifecycle to push session data to the xConnect Collection Service. When the xConnect Collection Service is down, Sitecore CD will wait until services are restored and then push data from the sessions.
If using InProc session management, and the CD server recycles it's app pool before it's able to push the session to the Collection Service, that session information is lost.
Recommended practice is to use a Session database like SQL or Redis.
If the xConnect Collection Service is down, Tracker and xConnect Submit batches will fail. This will mean personalization will not fire, but the Site will still work.
Assuming there's a Session Cookie, session data will still collect.
If the xConnect Reference Data service is down:
If xConnect Collection Search Indexer is down, the processing pools will not hydrate and the processing server will not do anything.
If the xConnect Reference Data service is down, Processing will error out with xConnect Issues. The processing pool should remain until the problem is resolved.
The Reporting Role of Sitecore does not have a dependence on xConnect. Merely the Reporting Database in SQL.
If this service is down, no collection of data from the CD (or CM if running the xDB migration tool) will occur.
If this service is down, the xdb index will not update.
If this service is down, Marketing Automation Engine and Sitecore Analytics will not work.
If this service is down, Marketing Automation plans will not advance.
If this service is down, reporting in Marketing Automation will not work.
If this service is down, ML Cortex processing will not work.
Well i just tried on an otherwise empty install of 9.1.
At least the homepage and a basic edit and publish would work. Other stuff like Experience Profile would just say An error has occurred.
It would be far safer to run an instance of XM1 instead.
