I have a Solaris (open indiana) system which is getting poor disk write performance. In order to enable ZIL in this version of zfs I need to add a line to /etc/system. This will not take affect until I've unmounted and remounted the zpool. The trick is that this spool is shared via nfs to about 200 other servers to host users' home directories. I can guarantee that no users will be accessing the disks during this period of maintenance but I would like to avoid having to issue an unmount for 200 systems in order to unmount the disk on the Solaris box.

My question is, with sharenfs, is it necessary to have all systems disconnected before unmounting the filesystem on the host? If it's possible, how do you go about it? I've tried unmounting already, the normal way, and it reports the disk is busy. There is no lsof in Solaris and pfiles (I think that's what it was) does not show anything obviously using the mounts.