PostgreSQL with Hot Backup

PostgreSQL 18 with automated weekly full backups and continuous WAL archiving for point-in-time recovery.

Services

Service	Description
postgres-db	PostgreSQL 18 with WAL archiving enabled
postgres-backup	Sidecar that runs weekly full backups via pg_basebackup

Quick Start

cp .env.example .env  # edit with your credentials
docker compose up -d

Configuration

Environment variables in .env:

Variable	Description	Default
POSTGRES_USER	Database user	postgres
POSTGRES_PASSWORD	Database password	—
POSTGRES_DB	Default database name	postgres
PGPORT	Host port for PostgreSQL	5432

Backup Strategy

Full Backups (Weekly)

• pg_basebackup runs on startup, then every 7 days
• Stored in /data/backup/postgres/full/full_<timestamp>/
• Hot backup — no downtime required

Incremental via WAL Archiving (Continuous)

• PostgreSQL archives Write-Ahead Log segments as they complete (~16MB each)
• Stored in /data/backup/postgres/wal/
• Captures every transaction between full backups

Backup Location

/data/backup/postgres/
├── full/
│   └── full_2026-03-06_12-00-00/   # weekly full snapshots
└── wal/
    ├── 000000010000000000000001      # archived WAL segments
    └── ...

Restore

To perform point-in-time recovery:

1. Stop PostgreSQL
2. Replace the data directory with a full backup:

   cp -r /data/backup/postgres/full/full_<timestamp>/ /path/to/pgdata/
   

3. Create a recovery.signal file in the data directory
4. Configure restore_command in postgresql.conf:

   restore_command = 'cp /data/backup/postgres/wal/%f %p'
   

5. Optionally set recovery_target_time for a specific point in time:

   recovery_target_time = '2026-03-06 14:30:00'
   

6. Start PostgreSQL — it will replay WAL files and recover

Monitoring

# Check backup service logs
docker compose logs postgres-backup

# Check WAL archiving activity
docker compose logs postgres-db | grep archive

# List full backups
ls /data/backup/postgres/full/

# List archived WAL files
ls /data/backup/postgres/wal/

Volumes

Volume/Mount	Purpose
postgres_data (Docker volume)	PostgreSQL data directory
/data/backup/postgres/wal	Archived WAL segments
/data/backup/postgres	All backups (full + WAL)