Our Legacy check for monitoring SnapVaults on 7-Mode systems will soon have an option to monitor lag-time as well. Just like its C-Mode counterpart, it can therefore monitor state as well as lag-time. Should the lag-time exceed a certain length, an alarm is sent.
./check_netapp7_snapvault.pl -H filer ... --what=lag-time -w 30min -c 1h
The configuration above would send a warning after 30 minutes and a CRITICAL alarm after 1 hour.