CODEWITHSUNDEEP
sql-serversql-server-2008azurecloudazure-storage
Dave New
Dave New

Reputation: 40022

Azure VM: SQL Server database on OS Disk or Data Disk?

I am busy migrating to Azure Virtual Machines.

Should my SQL Server database MDFs reside on the OS disk or on a data disk (which, as far as I understand, is a page blob - also known as a Azure Disk Drive)?

I would have thought the data disk was the correct place, but I've just read here that it is slower than the OS disk.

Furthermore, if I use a data disk then should the OS disk and data disk belong to the same storage account container for increased performance?

Upvotes: 2

Views: 3253

Answers (1)

Pat Filoteo
Pat Filoteo

Reputation: 1026

The short answer is that you want to use Azure Data Drives.

Longer answer with explanation: There are two models for persistent storage in Azure: Azure Drives & Azure Data Disks

They have some common features but there are some differences.

For both cases, they are backed by a PAGE Blob. The maximum size is 1TB per drive.

Where they differ is how they are exposed to the VM & communication paths.

Azure drives was the first implementation and was designed to allow Web/Worker/VM Roles to mount a blob as persistent storage with access via NTFS (i.e. allow legacy PaaS apps to interact with Blob storage without changes). They are implemented as a filter driver that runs inside of the Guest VM.

Azure Data Disks are part of the IaaS feature set. They are exposed to the Guest VM as a SCSI drive - so you can have multiple drives & create stripe sets for better performance.

For a detailed description & additional links/instructions/scripts

http://msdn.microsoft.com/en-us/library/windowsazure/jj672979.aspx

Upvotes: 3

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