When this option is set to Yes (as it is by default), Virtualmin will create a separate Cron job for each virtual server that has Webalizer enabled, in order to generate a report from its logs on a daily basis.

However, on a server with a large number of domains you may instead want to change this option to No, and instead manually schedule the command `/usr/libexec/webmin/virtual-server/run-all-webalizer.pl` using Cron. This will ensure that Webalizer is run for each domain in turn rather than potentially having multiple domains processed at the same time, and gives you more control over exactly when the processing is done.