I was patching our DB Servers this morning and encounteredenter image description here a really strange error when failing over some Availability Groups :

In our environment, we are running a somewhat unconventional setup, but it works well. We have 85 Databases, running SQL Server Standard, so each DB has its own Availability Group. What we do as a default, is to actually "Load Balance" the availability groups between the 2 servers. This means by default, we only have about 42 databases on each node, until patching where I failed all the DB's over to one node, and that when I received the error on about 24 databases.

In initial investigations, I found that you can only have 64 NetBIOS names per resource. Are Availability Groups not their own resource? In another article, they talk about ensuring you have no duplicate IPs or DNS names. I can confirm that we have no duplicates of either.

Is it a possibility, that on SQL Standard, you can only have 64 availability groups per database?

Please help with any potential resolutions. Thank you very much for your time.

1 Answer 1


The Microsoft EnableNetBIOS documentation states:

There is a limit of 64 NetBIOS devices in the cluster.

You should be able to just ignore this--disabling NetBIOS on clusters is recommended and SQL Server doesn't need it. See Speeding Up Failover Tips-n-Tricks.

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