Both the memcached dashboards have a new trending error:
> Memcached error for key "WANCache:v:enwiki:image_redirect:254363f3d14af58bbe12c644ee69ccf7" on server "/var/run/nutcracker/nutcracker.sock:0": A TIMEOUT OCCURRED
This exact error for that exact key is being reported about a 200 times per minute (of the 220 events per minute in total).
It seems equally distributed among the different mw hosts.
It started right after midnight, 2015-06-18 00:00 UTC.