db1095 doesn't have so much available space whereas db1102 still has around 2T.
The current size of commons on db1095 is:
root@db1095:/srv/sqldata# du -sh commonswiki/ 714G commonswiki/
Even though db1095 needs to be migrated to multi-instance soon, we should move ahead and place s4 on db1102 and point the labs hosts to replicate from it.
These is a draft of the steps needed:
- Stop 's4' thread on db1095 and note down position and binlog
- mysqldump (or mydumper, or xtrabackup) db1095 for commonswiki
- Add s4 in db1102 puppet's files
- Copy the content to db1102
- Start replication on db1102 (its master will be db1064) and make sure it replicates fine.
- Stop replication on db1064 and make sure db1095 and db1102 stopped at the same position
- Move labsdb1009,10 and 11 s4 thread to replicate from db1102. Do not start replication yet
- Note db1095 replication position for s4 thread and set default_master_connection='s4'; reset slave all;"
- Configure and start replication on labsdb1009,10 and 11 for the new 's4' thread replicating from db1102
- Start replication on db1102 from db1064
- Leave it a few days and then remove commonswiki database from db1095