We have a SQL Server 2008 R2 which has, among others, a 12K RPM HDD and a 7.2K RPM HDD. The original intention was to store the data files on the 12K drive and the log files on the 7.2K drive, as is our usual practice. However, a DBA has advised that this may not be the ideal configuration and that we may see better performance storing both the data and log files on the 12K HDD.
Not being a DBA, I'm quite happy to defer to an expert, but I'm not fully convinced that this configuration is the best approach. I would have thought that there would have been advantages in separating the data from the logs in terms of parallelism regardless of the specs of the HDD's.
What are your thoughts?