Can't delete device from metaset in Sun Cluster 3.2

I have a metaset defined in a Sun Cluster 3.2 environment.  In the zone xml I reference a file system /xyz that is a device (dnn) in the metaset and I want to delete that device.  I have shutdown the zone and umounted the zone filesystem, but when I try to metaset -s <name> -f -d /dev/did/rdsk/dnn, I keep getting:
metaset:  <node-name>: <metaset-name>: drive dnn is in use.

I have tried several things, but I keep getting the "in use" message.  Who has it and how do I get it to let go?

Thanks!