The SQLCAT team have published another excellent whitepaper – this time the long-awaited one on the SQL Server 2008 data compression feature. Thirteen people inside and outside Microsoft (including me) provided technical reviews and the authors (Sanjay Mishra along with Marcel van der Holst, Peter Carlin, and Sunil Agarwal) did a great job. I remember leading an effort back in 2005 to see if we (the SQL team) could get some form of data compression into SQL Server 2005 RTM (no, obviously) so it's great to see data compression out there and now with top-class proscriptive guidance on when and how to use it.
Bottom line: don't just go an turn it on without analyzing whether you'll get a decent compression ratio and your workload is suited to data compression.
You can get to the whitepaper at: Data Compression: Strategy, Capacity Planning and Best Practices and I'll add it to our Whitepaper Links page.