Yes... OC UM is a direct reference to OnCommand Unified Manager. WFA 2.1 will be able to work with OC UM 6.0 as Prakash indicated. OnCommand Unified Manager 6.1 will not be available at the time WFA 2.1 is released.
The issue is with the version of OnCommand UM 6.0 Beta you are running. I'm not certain which build that is, but if it is very early, then it doesn't have one of the tables WFA 2.1 is looking for, and hence, the error message. I ran into this as well early on. I no longer had this acquisition issue once I was able to install a newer version of the OnCommand Unified Manager 6.0 Beta,
Hope this helps,
Re: Does WFA 2.1 support connecting to UM 6.0 or 6.1?
The good thing is that if you have reached this error then you are doing the right steps to add a OCUM 6.0 Data source. So don't worry on that.
The bad things is that this error has been at some rare/odd times seen in our lab environment. The reason is that your OCUM 6.0 is monitoring one or more clusters that have been undergoing reset/upgrade and must be in some transient state. Looking at your error it looks like some of the disks in some clusters have been removed/unassigned etc and hasn't reached a stable state.
To get out of this error, you need to manually identify those culprit clusters. Your OCUM must have generated some events and you can look for them to help you. Once identified you can delete those clusters from OCUM. After this you WFA Data source acquisition should succeed. Yes, you of course won't have data for those clusters. But it should matter as your those clusters can't be used for anything in this state.
Get those clusters in a stable state and then re-add them to your OCUM. Acquire the Datasource again and this too work fine.
If this post resolved your issue, help others by selecting ACCEPT AS SOLUTION or adding a KUDO.