[Linaro-validation] Winter cleaning the Lava database/job history

Hey all,

Our lava instance is currently well over 120.000 jobs ran, which is great.

Unfortunately this means we've got quite a lot of historical data, the postgresql database is around 45 gigs and well over 600 gigs of job output data in the filesystem. We'd love to trim that down somewhat to more sensible sizes by pruning the older job information. Are there some guidelines on how to do that (and or tools available for)?