DAS or SAN for SQL Server part II

I thought a follow up was adequate for this one. After looking for some more views, oppinions and recommendations, I found the following posts (3 part) on the blog for the Microsoft SQL Server Development Customer Advisory Team:

Deploying SQL Server with SAN #1
Deploying SQL Server with SAN #2
Deploying SQL Server with SAN #3


There are many different oppinions out there, but I usually pay special attention to what Microsoft says since they are as close to the products as possible. At least I found this information valuable as kind of a formal reference. Look at separation of I/O based on the characteristics for each category of file types that SQL Server ulimately read and write from/to as a good example (often argued by the SAN guys - "we want to maintain a single array of disks instead of hooking a set of disks to a LUN"). And as argued earlier, SAN's complicates and often blurres the picture when dealing with performance issues when you are sharing the SAN with other applications/usage patterns (dedicated SAN to SQL Server is a good thing).

In my oppinion it's important to get every piece in a solution configured as optimal as possible from the start to secure a best practise deployment. A best practise deployment will again make sure that you have control over the deployment with regards to configuration and setup, when for instance performance issues arise. Under these circumstances, it's a lot easier to narrow down the scope for the activities necessary to diagnose the issue (similar to what the doctor does when you feel ill).

And the different SAN vendors add some more to the table where each vendor has it's own set of recommendations and of course some invaluable piece of magical software solving every challenge.

As you probably have noticed, I'm a simple man trying to live by the prinicple "Keep It Simple Stupid", but this is not an easy rule to apply in the world where IT technology plays a key role in every business.

It would be interesting to gather some comments around this matter, so come on and post your comments preferably in the form of real world experiences.

So long.