Hi Scott,
We have seen this error message because the hostname of the server is not the same name as the DNS record. I will try to explain it, but it may get a little convoluted.
The host name of the source filer for the snap mirror is actually FILER (I know, original, right?), but there is no DNS record for that name, so the destination filer is not able to locate it by that name. There is a DNS record for the source filer under a different name, we'll use FilerDNSName for this discussion. The destination filer needs to use this FilerDNSName in order to set up the snapmirror, which is done from a command prompt on the filer.
The problem comes in when adding the machine to OnCommand. No matter how we do that (using the name "FILER", FilerDNSName, or its IP address), OnCommand identifies the filer by its hostname and from then on referrs to it that way. So the system gets added to OnCommand as "FILER". OnCommand looks at the SnapMirror set up using FilerDNSName and cannot make the connection between "FilerDNSName" and "FILER" so it reports that "FilerDNSName" is not a managed system...
We have not found any way to resolve this. The status of the SnapMirror is accurately reflected in OnCommand, we just have to ignore the error message, and if we want to manage that particular SnapMirror we have to do so from a command prompt on the destination filer.
Hope it helps,
~Greg
