https://tools.wmflabs.org/replag/ shows 8 hours for lot of wikis.
c1.labsdb Shard Lag (seconds) Lag (time) s1 11473 03:11:13 s2 0 00:00:00 s3 11473 03:11:13 s4 0 00:00:00 s5 11473 03:11:13 s6 0 00:00:00 s7 0 00:00:00 c3.labsdb Shard Lag (seconds) Lag (time) s1 29811 08:16:51 s2 0 00:00:00 s3 29811 08:16:51 s4 0 00:00:00 s5 29811 08:16:51 s6 0 00:00:00 s7 0 00:00:00