Just a quick blog and reminder for something I worked a couple of months ago, or even longer and it took a considerable amount of time to figure out. Then last week a colleague just ping me with a question about a case they have been dealing for quite sometime.

讓客戶滿意是我們工作的目標，不斷超越客戶的期望值來自于我們對這個行業的熱愛。我們立志把好的技術通過有效、簡單的方式提供給客戶，將通過不懈努力成為客戶在信息化領域值得信任、有價值的長期合作伙伴，公司提供的服務項目有：國際域名空間、網絡空間、營銷軟件、網站建設、肥西網站維護、網站推廣。

Upon trying to join a second DAG member, in a virtualized Hyper-V environment, the following error message is presented:

“WriteError! Exception = Microsoft.Exchange.Cluster.Replay.DagTaskOperationFailedException: A server-side database availability group administrative operation failed. Error The operation failed. CreateCluster errors may result from incorrectly configured static addresses. Error: An error occurred while attempting a cluster operation. Error: Cluster API ‘”AddClusterNode() (MaxPercentage=100) failed with 0x5b4. Error: This operation returned because the timeout period expired”‘ failed.. —> Microsoft.Exchange.Cluster.Replay.AmClusterApiException: An Active Manager operation failed. Error: An error occurred while attempting a cluster operation. Error: Cluster API ‘”AddClusterNode() (MaxPercentage=100) failed with 0x5b4. Error: This operation returned because the timeout period expired”‘ failed. —> System.ComponentModel.Win32Exception: This operation returned because the timeout period expired”

If you look at the cluster logs you would notice the heartbeat failing on port UDP 3343.

Obviously you need to go by the normal troubleshooting steps of network connectivity and firewall rules. If everything seems right, and as my friend pointed out all knobs were turned and he was ready to give up. That’s when I asked…

Have you disabled TCP/UDP Checksum offload on both host and guest network cards ?

After disabling these options on both guest and parent partition cluster could be formed without any issues.

So in this case, after you make sure the obvious have been checked out and you still cannot join your cluster nodes in a virtual environment, take a look at the NIC properties for TCP/UDP Checksum Offload for IPv4 and IPv6.