Hello,

Here is an update on the ongoing work to move the links tables of Commons to a dedicated cluster (x4).

On Monday, September 7th, we will switch production reads to the new x4 cluster. At this point, the x4 hosts are just replicas of the s4 hosts, so the data served is identical.

On Tuesday, September 8th, we will take the x4 hosts out of that replication and we will switch the writes to x4 as well. From that point on, the affected tables will no longer be written to s4. They will remain present in the wiki replicas, but will no longer receive any updates. A wiki replica for x4 will be set up afterwards; this can't happen earlier, as we do not have enough disk space to run replicas for these tables on both clusters at the same time.

The following tables are affected by this move:

* linktarget * externallinks * pagelinks * templatelinks * categorylinks * collation * imagelinks * globalimagelinks * iwlinks * existencelinks * langlinks

The page and redirect tables will be present in both clusters.

Progress is tracked at: https://phabricator.wikimedia.org/T437108 and https://phabricator.wikimedia.org/T437111 Background/rationale: https://phabricator.wikimedia.org/T398709

Thank you, Alexander Vorwerk — IRC: Zabe