Kibana, the software running
logstash.wikimedia.org, as well as
elasticsearch, the server behind the scenes storing all the logs, have both
been upgraded today to their latest versions. Several historical indices
could not be directly loaded into the new servers and instead have been
dumped and are being reloaded. This reloading process may take some time,
so please be patient. The data will be there sooner or later :)
Play around with them, and create tickets in the wikimedia-logstash project
for any issues you find.