We need to failover the primary database master for s1 (enwiki) due to some network maintenance (T183585) affecting its rack and the fact that it is running on old hardware that will be decommissioned (T186320)
We would need a 30 minutes read-only window for enwiki, although if everything goes fine, it should be just a few minutes.
**Date: 18th July
Time: 06:00AM - 06:30AM UTC
Impact: enwiki will go read-only. No edits will be allowed. Reads will not be impacted.**