Issues on Windows Server 2012 and 2012 R2 with VMQ and Emulex network adapters

There have been several reports of networking and stability issues on Windows Server 2012 and Windows Server 2012 R2 when deployed on hosts equipped with Emulex NICs.  These issues arise when VMQ is enabled.  The typical symptoms include the loss of network connectivity on one or more virtual machines or an inability to shut down… Read more

Name Resolution Performance of Windows DNS Server 2012 R2

(This article has been updated with new set of results here ) This article details the name resolution performance of the windows DNS Server 2012 R2, when deployed in a strictly authoritative mode on which recursion has been disabled and root hints have been removed. Machine Configuration The tests were performed on a physical machine… Read more

Debugging performance issues with VMQ

In my last posts about VMQ (virtual machine queues), VMQ Deep Dive, 1 of 3, I tried to give readers a thorough understanding on the technology and why it was needed. Unfortunately, I still feel like there’s a piece missing around troubleshooting suspected VMQ issues. Therefore, in this blog post I’d like to address these… Read more

DNS Zone Level Statistics

  The Microsoft DNS Server provided certain server level statistics which enabled an admin to track the usage pattern or monitor DNS server performance. The statistics provided includes server wide query statistics, zone transfer statistics, packet statistics, different record statistics, DNSSEC statistics etc. ( For more details on DNS Server level statistics see http://technet.microsoft.com/en-us/library/jj649858.aspx )… Read more

VMQ Deep Dive, 2 of 3

Introduction In my last blog post of this series, ‘VMQ Deep Dive, 1 of 3,’ I went into detail on why we implemented VMQ and how to view the VMQ settings on the adapter to verify that it was configured properly. In this blog post I am going to explain Static v Dynamic VMQ and… Read more

VMQ Deep Dive, 1 of 3

Virtual Machine Queues (VMQ) is an incredibly powerful performance technology introduced in Windows Server 2012. A concern we’ve noticed as Windows Server 2012 is increasingly deployed in datacenter environments is misconceptions about VMQ, and even “tribal knowledge” that disabling VMQ solves networking issues. With a set of three blog posts on VMQ, we are going… Read more

Understanding IPv6, 3rd Edition has been published!

I recently heard from Joe Davies that the 3rd edition of his Understanding IPv6 book is available!     This edition builds on the treasure trove of information found in Understanding IPv6, 2nd Edition, which included updates for Windows Vista and Windows Server 2008. Understanding IPv6, 3rd Edition also adds details for Windows 8, Windows… Read more