How to set logs time retention?

Dears, I have to set log retention time like: 365 days totaly being 90 days access online, could you help me?

In time: I’m using Greylog open souce.

Thanks in advance!

please check the docs on index sets:

http://docs.graylog.org/en/3.1/pages/configuration/index_model.html#index-set-configuration

You might want to have daily rotation and hold 90 indices?