Migrating AWS RDS PostgreSQL to AnubizHost

Logical replication requires PostgreSQL 10+ and rds.logical_replication parameter set to 1 in the RDS parameter group. Apply the change and reboot the RDS instance (a one-time maintenance window). Verify with SHOW wal_level - should return logical.

Create a replication user on RDS with REPLICATION privilege: CREATE ROLE repuser WITH REPLICATION LOGIN PASSWORD 'xxx';. Grant SELECT on all tables: GRANT SELECT ON ALL TABLES IN SCHEMA public TO repuser;.

Order an AnubizHost VPS with enough disk for the database plus 30% headroom and enough RAM for the working set. Install PostgreSQL matching the RDS major version (15, 16, etc.):

apt install postgresql-15 postgresql-15-pg-stat-statements

Tune postgresql.conf: shared_buffers 25% of RAM, effective_cache_size 75%, wal_level=logical, max_replication_slots=4, max_wal_senders=4. Restart and create the target database.

Dump schema only from RDS:

pg_dump --schema-only -h rds-host -U doadmin dbname > schema.sql
psql -h localhost -U postgres -d dbname < schema.sql

On RDS: CREATE PUBLICATION migration FOR ALL TABLES;. On AnubizHost: CREATE SUBSCRIPTION migration CONNECTION 'host=rds-host port=5432 user=repuser password=xxx dbname=dbname' PUBLICATION migration;. Replication begins. Monitor lag with SELECT * FROM pg_stat_subscription;.

Wait until pg_stat_subscription.last_msg_receipt_time shows current timestamp - this means logical replication is caught up. Stop application writes for ~10 seconds, verify final state matches, then point connection strings at the AnubizHost host. Drop the subscription to disconnect from RDS: DROP SUBSCRIPTION migration;.

Update application DATABASE_URL and restart. Validate read and write paths. Keep RDS active for 24-48 hours as rollback.

Set up nightly base backups with pg_basebackup to an AnubizHost storage VPS. Configure pgBackRest for incremental backups if your database is large. Install Prometheus + postgres_exporter for monitoring. Related reading: database hosting, PostgreSQL migration overview, EC2 migration.