SQL on Azure VM Disk Striping and Location of Data/Log Files

Question

Per the Performance best practices for SQL Server in Azure Virtual Machines documentation:

https://docs.microsoft.com/en-us/azure/virtual-machines/windows/sql/virtual-machines-windows-sql-performance

There is a note with regards do disk striping:

Use data disks for data and log files: If you are not using disk striping, use 2 Premium Storage P30 disks where one disk contains the log file(s) and the other contains the data and TempDB file(s). Each Premium Storage disk provides a number of IOPs and bandwidth (MB/s) depending on its size, as described in the following article: Using Premium Storage for Disks. If you are using a disk striping technique, such as Storage Spaces, you must place all files on the same drive.

Is there a specific reason why this would be the case?

Answer 1

Is there a specific reason why this would be the case?

If you are using two disks where one disk contains the logs files and the other contains the data and TempDB files, so the paths are different.

Let's say, disk1E:\ for log files, disk2F:\ for data files, so your data default location is E:\, your Log default location is F:\.

If you don't want to use two disks for SQL, you can use a disk striping technique, such as storage spaces, in this way, you should change log files path and data files path to the same drive.

For example, you create a storage spaces, the path like E:\, your Data default location should be E:\dataand log default location should be E:\log, like this:

Hope this helps.