What's the optimal method to archive a lot of mailings?
We have done some recent work on an Extension through which you can nominate a 'before' date and it then cleans out the Mailings along with the abundance of Activities, Activity Contacts etc.

So this is not 'Archiving' as per the OP, this is deletion and does not answer your question but am hoping it proves a useful answer for others who might stumble on this. We will be writing up a blog shortly. On the big databases we are testing this on it is clearing out millions of rows of data and speeding up other queries particularly related to Actvities.

Extension is at https://github.com/jitendrapurohit/nz.co.fuzion.deleteoldbulkmailings

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