We see a slow memory leak in Apache that overtime causes out of memory errors. We suspect it’s a cron issue, but we’re not certain yet. Our multisite is failing with out-of-memory errors.
I was reading through some old posts on your support site and cron off-loading looks promising, but I really couldn't tell if we would need to create cron scripts for every site in the multi-site or not. This article was the most relevant: https://premium.wpmudev.org/forums/topic/how-to-switch-from-wp-cron-to-server-cron
We're running on a Oracle Linux 7 system using Apache 2.4, PHP 7.1 and mod_php.