Average number of log events generated by your servers?

I am in charge of migrating a PCI-DSS compliant platform to Amazon AWS, and I am currently exploring all the options I have for centralized logging before choosing the right solution.

I got interesting comments here, most suggest using AWS Cloudwatch as a centralized logging service before doing anything else with the logs (most likely handing them off to Elasticsearch).

The problem I've got while experimenting Cloudwatch on debian was that its agent component adds an always running cron job which inserts two new events per minute (session opened/closed for user root) to /var/log/auth.log. This corresponds to 2880 useless events per day. And moreover this number equals 80% of my total events.

Any guidance on this would be very helpful, in particular what is the average total of logs generated by your servers, and what is the average of useless logs entries if you ever had to log that.

Edit: I am interested in having various point of views whatever the systems are, though in my case I have standard zero overhead stacks (apache, wildfly, activemq among very few others). The usage may reach 10K transactions per day but this is relative, if I can have some statistics for 100 transactions/day I can do the maths.