Configuring physical storage for a Microsoft SQL Server installation

I'm configuring a Microsoft SQL Server installation which will use a SAN for storage. For SAN storage I have: - A small number of SSD disks - A larger number of 10K disks My SAN supports storage tiering. I'm on the fence about how to use the SSD disks. Here are the options that come to mind: - *Option 1:* Create tiered storage with the SSDs and 10K disks and use auto tiering to move highly accessed data to the SSDs. Then break that storage pool up into several different drives. - *Option 2:* Place key (I/O intensive) data on the SSDs and throw everything else on the 10K disks. **Questions** I don't have enough SSDs so that everything can reside on SSDs. So what's most important performance wise for SSD storage? tempdbs? LDF files? MDF files? My database is more write intensive than read intensive (if that makes a difference). Secondarily, are there any best practices I should follow when setting up the drives? Should I have separate drives for each tempdb? LDF files? MDF files? What about the system databases like master, model etc., should those go on their own dedicated drives or maybe on the C: drive? **Server disk activiity** By the way, here is a screenshot of our existing database server disk activity. It seems the tempdbs are the most read/write intensive followed by our MDF file and surprisingly the LDF file seems to have the least I/O. Any advice would be appreciated.