I looked at http://dumps.wikimedia.org/backup-index.html for "labs" or "wikitech", but didn't find anything. The wiki at wikitech.wikimedia.org should have occasional dumps/backups.
I believe as wikitech is outside of the cluster, this wouldn't fall under dumps.wikimedia.org, per se, but it should be simple enough to use the same scripts and host the dumps somewhere.
Maybe do a dump every six months or something?
Version: unspecified
Severity: enhancement