Throwaway account so keep this comment separate from my main account.
I used to work within the Office group. The way that data is organized in Exchange is mind-boggling -- and not in a good way, IMO. Its design is from decades ago, and trying to understand how to find something really takes a lot of experience. Without going into any gruesome details of how it works, I'll just say that it is a HUGE hurdle to being productive for day-to-day work.
Similarly, I'm not surprised that there's some kooky way that the Teams folks shoehorned their data into the existing Exchange system -- they probably have no other way to operate at that scale without taking years in writing their own database system. (I can't imagine that using SQL Server to do this would be viable, either, given what they want to do and the capabilities already built on top of Exchange.)
> The way that data is organized in Exchange is mind-boggling -- and not in a good way, IMO. Its design is from decades ago, and trying to understand how to find something really takes a lot of experience
I assume you're talking about MAPI, which owes some of its baroque nature to X.400. It definitely comes from another time. It always struck me as over-engineered.
On the other hand, it has also been ridiculously successful.
To be fair exchange works quite well for mail and calendar, it syncs very fast, is easy to set up and the cloud version is easy to administer (i never had to admin an on-prem exchange but ive heard its not fun).
Using this infra for teams makes sense since it already works well. As one poster said, its probably via some hidden folder.
I wonder what they did with skype, did they actually integrate any of it into teams or just dump it entirely?
On-prem Exchange is usually fine. Migration is a pain, but for a mid-size org you can mostly just install it and use it. If you have multiple servers distributed globally and database availability groups and such, yeah, it gets to be its own thing, but that's because at that point you're huge and you're going to feel the pain no matter what platform you run.
Teams was built from Skype. The fundamental infra for communication (chat, video call) was pulled out of Skype as a separate component and integrated into both. Skype the client is completely sunset, but a part of its back-end will continue to be used.
Teams came from Skype. Skype Lync was just a client (so far as I know). Don't take my word for it though, I was not there during the transition, this is just my understanding from talking to the ones that were.
I know it's popular to dump on Microsoft and there are some valid reasons, this is not one of them.
There are so many companies and businesses that rely on offline data, or silo'd data than will be tied through their AD LDAP account permission, M365, teams included, is such a better option than hand rolling all of them and praying you configured every service correctly.
I don't think this is nearly as crazy as you may think at first glance
Imagine if it was just a hidden (special) folder in an Exchange mailbox.
Voila, you already have a well-known and widely implemented and tested message syncing solution both for content and status (read/unread)
I assume Windows Phone worked the same way with its text message backup. When you'd set up a new phone it would take a while for your Microsoft account to finish syncing during which new messages would trickle into the Messaging app in real time. In fact if your old phone was still on WiFi new messages would show up on both. Still more advanced 15(?!) years ago than my Android today
When you dig it up, it is totally crazy and the total shit that we could expect.
Nothing works really well nowadays with exchange (classic, new, web, ...) or Teams.
It is a complex layer based on sharepoint, that was not designed for that, because OneDrive is so bad that they have absolutely no way to manage a proper sharing of files between multiple persons, and so even less between teams and orgs.
I the nice things like that, if someone gives you access to their Teams but you don't have a "storage" license on their domain, you will be able to exchange messages but a lot of things will not work without explicit clear error.
And especially sending or receiving a file, image or anything in a chat conversation.
Good lord. It truly is a layer of dung layered upon more layers of dung.