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05. WAL, backups, DR

Monitor backup status, WAL archiving, and disaster recovery readiness.

note

This dashboard requires WAL archiving to be configured (pgBackRest, WAL-G, or similar). Without backup tools configured, panels will show "No data".

Purpose​

Track backup health to ensure:

  • Backups complete successfully
  • WAL archiving keeps pace with generation
  • Recovery point objectives (RPO) are met

When to use​

  • Daily backup verification
  • Investigating failed backups
  • Capacity planning for backup storage
  • Validating DR readiness

Key panels​

The dashboard is organized into four rows: WAL overview, WAL archiving, Replication slot retention, and Configuration and WAL producers.

pg_wal directory size​

What it shows:

  • Size of the pg_wal directory over time

Warning signs:

  • Steady growth = WAL is accumulating (archiving stuck or an inactive replication slot pinning WAL)

WAL generation rate​

What it shows:

  • WAL bytes generated per second
  • Helps size archive storage and bandwidth

WAL archive success and errors / WAL archive success rate​

What it shows:

  • Counts of successful vs failed archive attempts (from pg_stat_archiver)
  • The success rate as a percentage

Healthy state:

  • 100% success rate, errors flat at zero

Warning signs:

  • Archive failures = storage or network issues

Archive lag bytes / Archive lag time and files​

What it shows:

  • How far behind archiving is, in bytes, in time, and in number of unarchived files

Healthy state:

  • Lag near 0 (no backlog), consistent archive rate matching WAL generation

Warning signs:

  • Growing lag = archiving falling behind

Retained WAL by replication slot / Inactive replication slots​

What it shows:

  • WAL retained on behalf of each replication slot
  • Count of inactive replication slots

Warning signs:

  • An inactive slot retaining large amounts of WAL can fill the disk

WAL-related settings / Top queries by WAL bytes/s​

What it shows:

  • A table of WAL-related configuration settings (e.g. archive_mode, archive_command, wal_keep_size, max_wal_size, checkpoint_timeout)
  • The queries generating the most WAL per second (from pg_stat_statements)

Variables​

VariablePurpose
cluster_nameCluster filter
node_nameNode filter
db_nameDatabase filter

Backup tools integration​

This dashboard monitors PostgreSQL-level metrics. For tool-specific monitoring:

ToolWhat to monitor
pg_basebackupBackup completion time, size
pgBackRestStanza status, backup retention
BarmanServer status, backup catalog
WAL-GBackup list, WAL archive status

Troubleshooting​

WAL archive backlog growing​

  1. Check archive command status:

    select * from pg_stat_archiver;

  2. Verify archive destination has space

  3. Check archive command in postgresql.conf:

    show archive_command;

No backup metrics​

Ensure your backup tool exposes metrics that pgwatch can collect, or configure custom metrics for your backup solution.