I have never done database backups or ran the autorepair on any of the systems I have set up with them running for a few years with no trouble. I do run mysqltuner and adjust as it advises.It will advise you that it may not be accurate if mysql has been restarted in the last 24hrs so I ususally run it after a day or two after setting up and then usually every few days until the database is the full size when the storage drive is full and starting to overwrite footage.
System load will be in the top right of top. WIll show 3 figures. 1 min average, 5 min average and 15 min average. Zoneminder shows 1 min average I think.