You mean there are limits?!?

I had an interesting Twitter conversation recently. Someone was shocked when told that a single SharePoint server could handle tens of thousands of users. As an isolated point of fact, this is true.

But, there is a "but". And it is a huge one. Such support depends both upon what those users are doing, and what that SharePoint server is doing. Microsoft now has some excellent performance and capacity planning documents for SharePoint, and if you look at the one for WSS in a collaboration environment, you will see that even under their "heavy" usage scenario, up to 15k users could be supported. Dig a little deeper, however, and you notice a big assumption: only 2% of that usage is document management (DAV reading and writing).

Many people envision using SharePoint as a replacement for their regular network file shares. While there are any number of good articles pointing out why that isn't a good idea (at least not without some serious planning), they all rely on talking about the SharePoint side of things - stuff like the "2000 document limit" (which isn't really a hard-cap, but that's fodder for a whole different article). Even taking appropriate topology and taxonomy steps, heavy file-based SharePoint usage is going to significantly reduce the "rated" capacity of a SharePoint environment.

SharePoint Itself is Probably Not the Limiting Factor!

Yet with the "I can consolidate these file shares/servers into SharePoint" stars in their eyes, many of the reasons these separate systems exist in the first place are forgotten. In a non-SharePoint file-sharing scenario, would you envision 15,000 (or more) users accessing a single server, let alone a single file share within that server, on a day-to-day basis? Of course not! Now consider if the users are geographically spread out. Would you want to channel all of the current file-server usage in your remote offices through a single WAN link? Maybe you could consider it - if you have point-to-point fiber. But otherwise? I didn't think so.

So take SharePoint, which itself resides on a Windows server, and stores everything in SQL Server databases, and consider what an all-out consolidation would mean. The articles I linked to earlier can help you with the capacity and availability considerations for SharePoint itself, but don't forget that SharePoint is only one piece of the total puzzle. Your network, your geographical distribution, and other factors, need to play as large a role in your planning for SharePoint as they do with any other system in your enterprise.