How should I configure these disks on a SQL Server for a BI configuration? Assuming constant memory (32gb) and CPU (4), 2 x disk arrays, I have the following disks


2 x 150 (10k)
6 x 150 (15k)


They are all local disks.

My requirements


My DB is 350gb and set to default 10% growth
My OS &amp; SQL Server are Server 2k8R2 (C: drive OS + page + applications = 55Gb)
Log requirements are about 70gb and set to default 10% growth and is routinely truncated
My TempDb is about 12gb currently and set to default 10% growth


My problem is that I’m trying to understand where to best put the TempDB and OS and the Log. My experience is limited in optimal configuration of these two

This is not an online transactional system. It has heavy data write (new data + indexes rebuild/reorg) then heavy data read (I'm estimating at about 50/50) processing for about 13 hours, and then just quiet.

My understanding is that the TEMPDB is heavily used during normal processing compared to the log.

My idea is the following


2 x 150g (15k) Raid 1 = 150g for OS + TempDB
2 x 150g (10k) Raid 1 = 150g for LOG (note slower disks here)
4 x 150g (15k) Raid 5 = 150g for data


Does this sound like a good idea? I could then swap the Log + TempDB if needed.

Am I breaking a cardinal rules like never put TempDB on OS disk due to paging concerns, or perhaps never put log on slower disk than data?

Edit:

We also have a SSAS on the system and the end users access only the Cube. The 50% read above is based on the time it takes to process SSAS database.
2 * 10k RAID1 for OS, 6 * 15k RAID10 for everything else. Honestly, with this many disks 1 array is the safest and usually fastest bet.

If you've got time to test and have a real world, repeatable, measurable workload then by all means do a test run with your tempdb on the OS drive (caveat: limit tempdb file growth to ensure you don't splat the OS). Flip side, you may see moderate improvements to your data load and maintenance with the log there instead so worth a test run or two if time permits.