Ideas for future checks

• Check if Default Cache + Session + FPC are on different Redis instances
• FPC hit / miss percentage
• Cache flushes per hour
• Check if Magento version >= https://api.github.com/repos/magento/magento2/releases/latest
• TMP_TABLE_SIZE + MAX_HEAP_TABLE_SIZE http://devdocs.magento.com/guides/v2.2/config-guide/prod/prod_perf-optimize.html#magento---performance-optimizations
• Enable Zend OPCache with validate_timestamps=0 (or some other good value)