On of the major issues I see arising around any migration to SharePoint Foundation 2010 is the size of the content databases. The reason is that out of the box SharePoint Foundation 2010 is installed with SQL Server 2008 Express which has a 4GB database size limit. This is a pain because Windows SharePoint Services v3 (WSS v3) came with SQL Server 2005 Embedded Edition (#SSEE) which had an unlimited database size (even though it had other limitations).
Many of the WSS v3 implementations on SBS I have seen have now grown beyond 4GB, so what’s your options if you want to upgrade to SharePoint Foundation 2010? The first was to use SQL Server 2008 Express R2 which has a database size limit of 10GB and is a free download from Microsoft. This does require manually installation prior to the installation of SharePoint Foundation 2010 as well as manual set of SharePoint 2010. However, even 10GB I can see potentially being restrictive for some of the larger Companyweb deployments.
Beyond 10GB the only option that I thought was to upgrade to a full version of SQL (i.e. Workgroup, Standard, etc) but that means shelling out money. I have however now found an option that will support databases up to 16GB for free. That method is using Remote BLOB storage.
Basically, you can install SQL Express 2008 R2, then install Remote BLOB storage and then upgrade the databases. The process is detailed in this TechNet article:
http://technet.microsoft.com/en-au/library/ff628258.aspx - Upgrade a stand-alone installation on a domain controller by using Remote BLOB Storage (RBS) (database attach)
I haven’t tried it but it doesn’t seem much more difficult that installing an extra piece of software on the server and running an upgrade command. So where did I get the 16GB limit that Remote Blob Storage will support? Here:
http://technet.microsoft.com/en-au/library/ff628569.aspx - Plan for remote BLOB storage (RBS) (SharePoint Foundation 2010)
where it says:
If the content databases are larger than 16 GB, you must purchase Microsoft SQL Server 2008 R2, SQL Server 2008 with Service Pack 1 (SP1) and Cumulative Update 2, or SQL Server 2005 with SP3 and Cumulative Update 3 to support the databases instead of remaining on a free version of SQL Server.
I don’t quite see why you ‘must’ purchase an upgraded versions of SQL Server but I’ll take Microsoft at their word until I can test this further.
So there you have it. From what I can determine the largest content database you can run with on SharePoint Foundation 2010 is 16GB after which you’ll need to pay for a full version of SQL server.