Migration job metrics

Database Migration Service collects and displays migration job metrics that represent the health and progress of your data migration process. This page describes the following areas associated with migration job metrics:

Metrics available on the migration job details page

The migration job details page shows several diagrams that can help you understand the current state and progress of your migration job. You can filter the information in these diagrams for each database included in your migration job.

Example diagrams for migration job metrics Database Migration Service.
Figure 1. Sample observability diagrams in Database Migration Service. (click to enlarge)
Example diagrams for migration job metrics Database Migration Service.

Expand the following sections to learn more about each diagram and its associated metric.

Restore lag

The Restore lag diagram uses the migration_job/max_replica_sec_lag metric to represent the time difference between the backup file epoch (derived from the file name), and the moment when that file is fully restored in your Cloud SQL destination instance. You can use this information to estimate your average data replication speed, or to troubleshoot possible issues with continuous data replication.

This metric is available for each database included in your migration job, and in the aggregated view where it shows restore lag across all databases included in your migration job.

Transaction log backup upload lag

The Transaction log backup upload lag diagram uses the migration_job/sqlserver/transaction_log_upload_sec_lag metric to show how much time (in seconds) has passed between now and the timestamp of the last transaction log file you uploaded to Cloud Storage. You can use this metric to monitor possible issues with automated uploads of transaction log files: a big time difference could indicate that your transaction log files aren't being uploaded to the Cloud Storage bucket.

This metric is available for each database included in your migration job, and in the aggregated view where it shows the highest lag across all databases included in your migration job.

Processed transaction log backups

The Processed transaction log backups diagram uses the migration_job/sqlserver/processed_file_count metric to represent how many transaction log backup files Database Migration Service has processed and imported to Cloud SQL. This information updates after a transaction log is fully processed, so the line displayed on the diagram moves in bigger jumps rather than gradual decreases.

You can monitor this metric to track the progress of the incremental load phase. A value greater than 0 indicates that your migration job finished the initial load phase and is now in the incremental load phase.

This metric is available for each database included in your migration job, and in the aggregated view where it shows a summary for all databases included in your migration job.

Processed transaction log backups size

The Processed transaction log backups size diagram uses the migration_job/sqlserver/processed_file_bytes_count metric to show how much transaction log data (in bytes) Database Migration Service has replicated to your Cloud SQL destination instance. This information updates after a transaction log is fully processed, so the line displayed on the diagram moves in bigger jumps rather than gradual decreases.

This metric is available for each database included in your migration job, and in the aggregated view where it shows a summary for all databases included in your migration job.

Unprocessed transaction log backups

The Unprocessed transaction log backups diagram uses the migration_job/sqlserver/unprocessed_files metric to represent how many transaction log backup files Database Migration Service has detected in your source Cloud Storage bucket but has not yet replicated to your Cloud SQL destination instance. This information updates after a transaction log is fully processed, so the line displayed on the diagram moves in bigger jumps rather than gradual decreases.

You can watch this metric when you want to determine when to finalize your migration job. A good time to promote the migration job would be when the value of Unprocessed transaction log backups reaches zero and you don't have more transaction log files to upload to Cloud Storage.

This metric is available for each database included in your migration job, and in the aggregated view where it shows a summary for all databases included in your migration job.

Unprocessed transaction log backups size

The Unprocessed transaction log backups size diagram uses the migration_job/sqlserver/unprocessed_file_bytes metric to show how much data (in bytes) Database Migration Service has detected in your source Cloud Storage bucket but has not yet replicated to your Cloud SQL destination instance. This information updates after a transaction log is fully processed, so the line displayed on the diagram moves in bigger jumps rather than gradual decreases.

You can watch this metric when you want to determine when to finalize your migration job. A good time to promote the migration job would be when the value of Unprocessed transaction log backups size reaches zero and you don't have more transaction log files to upload to Cloud Storage.

This metric is available for each database included in your migration job, and in the aggregated view where it shows a summary for all databases included in your migration job.

Total destination storage usage

The Total destination storage usage diagram uses the Cloud SQL database/disk/bytes_used metric to show how much data (in bytes) is stored in all the databases in your destination Cloud SQL instance. You can use this information to estimate the progress of your migration job.

This metric is only available in the aggregated view. You can't filter the total disk usage per database.

View metrics on the migration job details page

To view metric diagrams on the migration job details page, perform the following steps:

  1. In the Google Cloud console, go to the Migration jobs page.

    Go to Migration jobs

  2. In the Jobs tab, click the display name of your migration job.

    The migration job details page opens.

  3. In the Databases section, you can view Restore lag and Unprocessed transaction log backups size numerical data for each database included in your migration job.
  4. Click the Monitoring tab to see the metrics diagrams.
    • You can use the View menu to show aggregated data for all databases included in your migration job, or filter the information for specific databases.
    • You can also view each diagram directly in Cloud Monitoring. Click More chart options > View in Metrics Explorer.

Metrics available in Cloud Monitoring

The following table describes all migration job metrics you can use to create charts in Metrics Explorer for SQL Server migrations. The complete metrics Database Migration Service metrics reference lists several additional metrics, but they are not available for SQL Server migrations.

You can also use the Cloud SQL cloudsql/database/disk/bytes_used metric and compare it with the total size of your source databases to estimate the migration job progress.

Metric type Launch stage
Display name
Kind, Type, Unit
Monitored resources		 Description
Labels
migration_job/max_replica_bytes_lag BETA
Max lag bytes of the migration job data.
GAUGE, INT64, By
datamigration.googleapis.com/MigrationJob 		Current replication lag, aggregated across all of the migration job's data. Sampled every 60 seconds. After sampling, data is not visible for up to 180 seconds.
database: Database name.
migration_job/max_replica_sec_lag BETA
Max lag in seconds of the migration job data
GAUGE, INT64, s
datamigration.googleapis.com/MigrationJob 		Current replication lag, aggregated across all of the migration job's data. Sampled every 60 seconds. After sampling, data is not visible for up to 180 seconds.
database: Database name.
migration_job/sqlserver/processed_file_bytes_count BETA
Processed Files Bytes Count
DELTA, INT64, By
datamigration.googleapis.com/MigrationJob 		Number of bytes uploaded to the destination. Sampled every 60 seconds. After sampling, data is not visible for up to 180 seconds.
database: Database name.
migration_job/sqlserver/processed_file_count BETA
Processed Files Count
DELTA, INT64, 1
datamigration.googleapis.com/MigrationJob 		Number of files uploaded to the destination. Sampled every 60 seconds. After sampling, data is not visible for up to 180 seconds.
database: Database name.
migration_job/sqlserver/transaction_log_upload_sec_lag BETA
Transaction Log Upload Sec Lag
GAUGE, INT64, s
datamigration.googleapis.com/MigrationJob 		The lag in seconds since the last uploaded transaction log. Sampled every 60 seconds. After sampling, data is not visible for up to 180 seconds.
database: Database name.
migration_job/sqlserver/unprocessed_file_bytes BETA
Unprocessed File Bytes
GAUGE, INT64, By
datamigration.googleapis.com/MigrationJob 		Unprocessed file bytes waiting to be uploaded to Cloud SQL. Sampled every 60 seconds. After sampling, data is not visible for up to 180 seconds.
database: Database name.
migration_job/sqlserver/unprocessed_files BETA
Unprocessed Files
GAUGE, INT64, 1
datamigration.googleapis.com/MigrationJob 		Unprocessed files waiting to be uploaded to Cloud SQL. Sampled every 60 seconds. After sampling, data is not visible for up to 180 seconds.
database: Database name.