Our ASP.Net website uses SQL Server as the session state provider. We currently host the database on SQL Server 2005 since it does not play well on 2008 R2. We would like to know why, and how to fix it.

hardware setup Our current session state server has SQL Server 2005 with the files hosted on a single local disk. It is one of our oldest servers since it has served us well, and we never felt the need to upgrade it. The database is about 2 GB holding 6000 sessions. (The sessions are a little big, but we need it.) We have another server with SQL Server 2008 R2 with a much faster CPU, much more RAM, and a much faster hard disk.

situation One day, we have a huge surge in traffic. The transaction log growth on SQL Server freezes the server for 10's of seconds, allowing only a few requests through in minutes. So we load up the new server with ASPState with very large data and log files and point all of our applications to the new server. It chugs along fine for about 5 minutes, and then the CPU usage jumps up to 50% of the 16 cores that Standard Edition can use and freezes for 10's of seconds at a time. The files do not record any autogrowth events. The disk queue is nice and low. RAM usage is low.

CPU usage on our old server has never been higher than 5%. What happened on the new server?

Alternatively, I would like to hear success stories with ASP.NET session state server running on SQL Server 2008 R2 with an average write load of 30MB/sec with bursts up to 200MB/sec.