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John Paul Cook

Running SQL Server 2008 in a Hyper-V Environment

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SQL Server 2008 does perform very well in a Hyper-V environment when properly configured, which among other things means don't use the default of dynamically expanding virtual hard disk. Hyper-V isn't at all like Virtual Server or Virtual PC. It's best to drop preconceptions drawn from experience with those products.

For best I/O performance in Hyper-V, use passthrough disks (this is when a physical disk is assigned directly to Hyper-V without using a vhd file). Fixed size virtual hard disks are a close second. Dynamically expanding disks and differencing disks provide convenience at the cost of performance and thus should not be used when I/O performance must be maximized.

High network traffic imposes a burden on the CPU when running on Hyper-V (this is also true of Virtual Server). If a SQL Server configuration is CPU bound on bare metal, it might not have enough CPU cycles left for optimal networking performance. Also, keep in mind that a maximum of four logical processors can be assigned to a Hyper-V virtual machine, so if your SQL Server configuration needs more than four processors, it is not suitable for Hyper-V.

Published Monday, October 6, 2008 8:50 AM by John Paul Cook

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About John Paul Cook

John Paul Cook is a database and Azure specialist in Houston. He previously worked as a Data Platform Solution Architect in Microsoft's Houston office. Prior to joining Microsoft, he was a SQL Server MVP. He is experienced in SQL Server and Oracle database application design, development, and implementation. He has spoken at many conferences including Microsoft TechEd and the SQL PASS Summit. He has worked in oil and gas, financial, manufacturing, and healthcare industries. John is also a Registered Nurse currently studying to be a psychiatric nurse practitioner. Contributing author to SQL Server MVP Deep Dives and SQL Server MVP Deep Dives Volume 2. Connect on LinkedIn

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