If the network share utilized space exceeds the quota what happens? Does it go to read only or go offline?
If the client writes data to the network share that exceeds the "refquota" value, then the client will get an error indicating the write failed due to lack of space.
To check the "refquota" value run the following command:
zfs get all|grep rfquota
They will then need to remove or archive data via the client to be able to write to the share again.
Please review the following link for additional detail: