I'm new in azure VM and need advice from the expert.

Is it good if placing the application file (website file) in OS disk azure VM? how about the performance ? I tested by placing only 1 site but it's seem like same if i put it in data disks.

the reason why I place the application file in OS disk is the charging of storage transaction in data disks. My web application have some code to read file and write it again.

Note : I only put the application file in OS Disk. I put SQL data files in data disks.


I would recommend storing these files directly to a storage account using the storage API that way you have access to these media anywhere from any of your web apps. This is the recommended scenario for scalability. If you place these files inside your azure VM, only this specific VM will have access to it.

Regarding using OS disk Vs Data Disks. First, storage transactions should not be a problem. We are talking $1 for 30million transactions. Second, OS disk or data disk are capped to 500IOPS of performance. You can, however, create a storage pool of several data disks to improve performance. In theory each data disk would add 500IOPS, ie. 4 disks = 4x500 IOPS (in practice it's not so linear).

  • thanks for the advice, this statement (We are talking $1 for 30million transactions) really open my mind. :) – zenixgrace Jul 21 '15 at 2:42

If you are using D or DS series machines you may place your application data on your OS disk and be benefited with performance about 1000 -10000 IOPS (depends on machine size). It`s only my experience.

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