As long as I'm blogging about filestreams...

Folks always want to know if the filestream information can be stored on a remote share. They look kind of disappointed when they hear that the filestream filegroup must exist on a local (to the SQL Server instance) drive. However... (isn't there always a however?)

For SQL Server 2008, the SQL Server team released a companion feature to filestream called remote blob storage (RBS). RBS consists of a set a stored procedures and an SDK that allows you to store your blob on a remote blob store. The SDK works differently than the filestream storage feature. And, to use the feature, you need a RBS blob store provider. Looking around, EMC² has an RBS provider for the Centera product line. And there's a sample provider and code to use it up on CodePlex.

The SQL Server team released the first version of RBS as part of the SQL Server 2008 Feature Pack.

They'd always said they'd be bridging the gap between filestream storage and RBS in future. We'll...the future is soon (or now, depending on how much you like CTPs). The November CTP of the SQL Server 2008 R2 Feature Pack comes with an RBS provider for Filestream. You still have to use the RBS APIs, but you can have your (filestream) cake and eat it too. Remoting. There's little info right now, but there are a number of postings on the RBS team's blog.  Including a comparison of filestream storage and RBS. In addition, RBS & filestream appears to hook into SharePoint 2010, but I'll leave the description of that to the SharePoint 2010 documentation (which has just been updated today).

And, BTW, if you were going to ask "Are features that appear in the SQL Server Feature Packs supported?", the answer is yes. I asked.

I was under the impression that the database engine/programming model changes in SQL Server 2008 R2 were minimal and could be counted on one hand. Today I was running an old demo that I had, having to do with filestreams on the R2 Nov CTP. Usually I run this one line-by-line, but I was in a hurry and ran the whole thing. Funny...I didn't remember this few errors caused by limitations when using filestream. Hmmm...

In SQL Server 2008 R2, filestream storage now support snapshots transaction isolation levels. Both flavors, read-committed snapshot and snapshot. This should expand the possibilities for using this feature because, in SQL Server 2008 (non-R2), you can't even enable either of these isolation levels at the database level if you have a filestream filegroup/column. Now, you can not only enable the levels, but the filestream goes exhibits the transactional semantics.

This is actually doc'd in the SQL Server 2008 R2 BOL, right here.  BTW, although the chart in the BOL lists the streaming access doesn't support ReadUncommitted, RepeatableRead, or Serializable iso levels, in my experiments, you don't use an error using these iso levels with streaming. The stream just doesn't exhibit the expected transactional semantics.

So you can count 'em on one hand, 'eh? Between this enhancement and the perf improvements blogged about recently on the SQL Server Storage Engine blog, maybe I'll need another hand.