Slow disk performance on Azure Virtual Machine

Solution 1:

Bit late to the party here, but for what it's worth "attached" SSDs in Azure have their IOPs throttled based on the machine size. It wasn't mentioned in the pricing anywhere but I raised this issue as a ticket with technical support when they referred me to the blog post below.

See this link: http://azure.microsoft.com/blog/2014/10/06/d-series-performance-expectations/

Solution 2:

Maybe it's not related to the memory. "Physical" disks on Azure uses what's called Blob storage and that's the reason the performance is not the same as in your local computer even with similar hardware. You can find more information on this link. This seems to be a common problem for the SQL Server community who relies heavily on disk performance. I'll quote an article i found about it

The Performance Guidance for SQL Server in Azure VMs whitepaper mentions (on pages 15 and 26) that in Azure VMs, Storage Spaces can be used to improve storage performance for SQL Server workloads

Storage Spaces is a built in feature of Windows Server 2012 that lets you use several physical disks to create one single virtual disk, hence as a work around for the I/O limitations of the VM disk itself. Quoting again:

With larger VMs that support many (up to 16) physical disks, a very significant increase in storage performance is possible. This can enable Azure as a viable platform for many SQL workloads that would be too constrained by the I/O performance of a single Azure disk otherwise.

This article will show you the steps to create a storage space.

You should try this first. Probably you can even use a smaller instance as the storage service is a separate service from the instance itself.