OK thanks just one last query, would the quota rule be something like this? quota_rule2 = Public*:storage=100M

=========== namespace public { prefix = shared. separator = . (...) } dict { quotadict = mysql:/etc/dovecot/dovecot-dict-quota.conf expire = mysql:/etc/dovecot/dovecot-dict-expire.conf } quota = dict:INBOX::proxy::quotadict quota2 = dict:shared:%d:ns=shared.:proxy::quotadict quota_rule = *:storage=50M:messages=1000 quota_rule2 = Trash:storage=50M:messages=100 quota2_rule = *:storage=100M:messages=1000

this currently works - you must use the prefix of the namespace as parameter in the quota-definition.