Migration job metrics

Database Migration Service collects and displays migration job metrics that represent the health and progress of your data migration process.

The following table lists and describes the migration job metrics that you can view on the migration job details page. You can view the following metrics for all databases included in your migration job or only the databases that you selected for migration:

Migration metric	Description
Replication delay	Use this metric when you consider performing a promotion of a continuous migration. Replication delay should be zero at the time of the promotion in order to avoid data loss. Note this metric is only relevant in the change data capture (CDC) phase. For more information on job promotion, see Promote a migration.
Storage usage in total bytes	Reflects how many GB are being used by the destination AlloyDB for PostgreSQL instance. Use this metric to get a rough indication of migration job progress.

You can view all Database Migration Service Cloud Monitoring metrics that relate to migration job performance in the Metrics Explorer. To view each diagram directly in Cloud Monitoring, click more_vertMore chart options > View in Metrics Explorer.

You can use the following metrics to monitor your migrations:

• The migration_job/initial_sync_complete metric indicates when the full dump phase is complete for a specific database or the entire migration job. You can view this metric on a migration level or a database level by applying the database label. If the database label is present, the metric value is for that particular database. If the label is not populated, the metric value is for the entire migration job.
• The migration_job/max_replica_bytes_lag metric shows the size of log data that are not yet replicated to the destination. You can view this metric on a migration level or a database level by applying the database label. If the database label is present, the metric value is for that particular database. If the label is not populated, the metric value is for the entire migration job.
• The migration_job/max_replica_sec_lag metric shows the time (in seconds) that the destination database is behind the source database. You can view this metric only at the migration level.

For more information about the Metrics Explorer, see Create charts with Metrics Explorer.