umount says device busy and fuser say s nothing

Hi,

I have come across this problem increasingly often now. umount ZFS filesystem says device busy but fuser says no process is locking. Is this a known issue? Any suggestions to what I can use instead? This time we have it on a newly created, (should be) never used, zpool in a two node cluster that we want to export prior to add it to a cluster resource group. Solaris 10 u8 and Cluster 3.2 is fairly up to date. This is a live prod system so reboot is not an option. Last time I had this problem I was lucky killing the right