Want your virtual environment to perform? Spend more money on storage.
Posted Saturday, April 23, 2011 in Alternative Solutions 0 comments
Even after a couple years at Virsto, I am still amused at advice to solve performance issues by wasting disk space.
Michael Otey, from SQL Server Magazine and Windows IT Pro, wrote this week a good article with 7 tips on how to optimize SQL Server on Microsoft Hyper-V.
One of his tips is a very common one: to get better storage IO performance out of Hyper-V, use fixed VHDs rather than dynamic VHDs. This is Microsoft's own recommendation for best performance.
But there's a reason why people want to use dynamic VHDs: they save disk space. A dynamic VHD doesn't pre-allocate precious, expensive disk space. It allocates only the space actually occupied by data. Fixed VHDs, on the other hand, will take up 127GB for that VM image, even if the actual content of the image is 12GB.
What we find odd is the suggestion to solve one problem by creating another. Yes, you can get better IO performance on fixed VHDs. But the price you pay is wasting a lot of disk space. How is that good?
With Virsto software, you can get better performance than fixed VHDs while taking up no more space than dynamic VHDs. Not to mention a whole lot of other benefits. Why would you do anything else?
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