At this point, the Office 365 service only allows for the retention of audit entries for 90 days. Can you provide us more information regarding your requirement to keep logs for 3 years. Is this a legal obligation? Please provide details around the specific audit entries you would like to retain for an extended period of time.
An error occurred while saving the commentAnonymous commented
There are a plethora of government regulations which require retention of data for periods much longer than 90 days. Honestly, I can't think of a single legal requirement that, if applicable to logs, would be any period of time measured in the "days." More like, the "years."
The workaround mentioned by Scott is obviously feasible, but definitely shouldn't be the only way available.