Microsoft
@ Samir Marwaha: While I have seen this DAG Wars issue occur on Mailbox servers, it would be advisable to ensure all servers (not only Exchange ones) have this setting disabled. When would I want a server NIC to go to sleep? Never would be my guess.
@ Heath Graves: This is one of the first 3 things I check rolling onsite. NIC settings, DAG IP's for each subnet that has a DAG member, and collapse of the DAG network. Any or all 3 can cause gremlin issues on randomly activating DB's in a DAG.
@ Tiago Ferreira de Souza: I have not dug into specifics if all or just some DB's are impacted. If the NIC only drops a few packets, then wakes back up, I could see that only some DB's could be impacted and not necessarily the entire server with all DB's
bouncing.
Again, ensure that all 3 steps are covered if you are having random DB's mounting for what appears to be no reason at all.
1. Disable NIC sleep mode
2. Ensure the DAG network is collapsed.
blogs.technet.com/.../exchange-2010-collapsing-dag-networks.aspx
3. Ensure that there is an IP assigned to the DAG where each DAG member lives in that subnet:
technet.microsoft.com/.../dd351172(v=exchg.150).aspx
Hope that helps.
