Data Management in SQL Database Cloud Migration

SQL database cloud global migration

Your firm is growing to a new region utilising Cloud SQL? Do you need to transfer Cloud SQL apps to a location with data compliance or geographic locality requirements? After a regional outage, you may need to migrate your Cloud SQL instance.

Enterprise customers may choose to upgrade to Cloud SQL Enterprise Plus for 99.99% uptime, near-zero scheduled maintenance, and 3x enhanced performance. All these scenarios require moving data to a new area and operationalizing apps to promptly serve consumers. This post will ease Cloud SQL migration, reduce complexity, and application downtime.

This blog article describes Cloud SQL regional migration planning:

1.Assess migration needs

2.Method of migration

3.Application enablement

Assess migration needs

When planning a migration, establish application-specific integration needs. These programmes use backend databases to determine regional migration:

What is the database size?

The database size influences migration time. Choose between online (replicas) or offline (export/import or backups) to regulate time. Online procedures are best for applications that cannot afford extensive downtime, whereas offline alternatives are easier to design and implement.

Do you tolerate downtime?

Production applications with Change Request schedules make migration difficulty easier to determine. If downtime is acceptable for change rollout, consider one-time migration instead of continuous migration.

How does the programme configure database connectivity?

Cloud SQL regional migration may involve application database connection configuration changes. If your apps currently use Cloud NAT gateway, Cloud DNS, or a load balancer to connect to Cloud SQL, altering their setup won’t affect them.

What is your database’s hourly update size?

Regional migration strategy options are heavily influenced by hourly database updates and transactions. Choosing a migration window with the lowest transaction frequency will help you prevent losing transactional data, user connection failures, application timeouts, excessive error rates, etc. This makes transaction frequency during migration hour crucial. Identifying the period when your instance has the least database traffic might simplify migration planning.

Is your client-side database encrypted?

Cloud SQL can encrypt and decrypt data for applications. Cloud key management solution stores data encryption and decryption keys. Regional or global KMS keys for data encryption affect Cloud SQL migration. Data may need to be re-encrypted using a single region KMS key, depending on the migration strategy. Refer to Cloud SQL encryption key interaction.

Answering the aforementioned questions helps you design the optimum migration strategy to transfer Client apps to Cloud SQL. This prevents client apps from splitting brains.

Approach to region migration

There are several ways to migrate Cloud SQL databases across regions. The next section discusses popular methods:

Region migration cross-region read replicas:

A read-only replica may provide reads without a round trip to the leader region since it holds the whole database. Read-only replicas give low-latency stale reads to nearby clients and boost a node’s read scalability to all clients. Cross-region replication makes it easy to build a fully managed read replica in a different area than the original instance.

The cross-region read replica asynchronously replicates the primary instance. This causes the read replica to lag behind the original instance. If the read replica is out of sync with the primary instance during migration, new data will be lost. To prevent replica from trailing primary instance During migration hour, the replica instance must track monitoring metrics.

When region expansion or business demands dictate migration, this cross-region read replica may be promoted to a standalone instance. In replica promotion circumstances, the Cloud SQL instance IP address may vary.

With zonal read replicas, Cloud SQL replica IP addresses match primary instances.

Regional read replicas have a different Cloud SQL replica IP address than the original instance.

Promoting a Cloud SQL regional read replica changes its IP address to the promoted primary instance. Applications are pointing to Cloud SQL’s primary instance IP, hence a config modification is needed to point to its regional read replica IP.

The complexity of repointing apps to new Cloud SQL instances relies on application settings. Cloud DNS config change is explained in Cloud SQL lab.

Data migration for new regional Cloud SQL instance:

Database Migration Service (DMS) may migrate databases from an existing CloudSQL instance to a new one with the same or a different edition in a different region and then replicate the source database into the target. DMS allows CDC-style migrations for all sources (homogenous and heterogenous) that continuously transfer changes. Check PostgreSQL DMS limits.

Backup restoration for new regional Cloud SQL instance:

To transfer Cloud SQL to another region, utilise automated or on-demand backups on multi-regional buckets. Cloud SQL instances from backup take longer to set up since they must be created and restored.

Export and import databases in new regions: Database exports enable migration to various regions. Organisational efforts, time, and data loss tolerance are key factors in export/import database selection. Regional migration can employ one-time export and import in multi-regional Cloud storage buckets accessed in the destination region.

Export/import should be automated to export databases regularly based on business needs for disaster recovery. What are your SLA needs? Are there GDPR compliance requirements when exporting data? What should data export frequency be?

Application enablement

Applications that use Cloud SQL have a database setup. The difficulty of switching configurations relies on how they are specified. Application runtime configuration defines database connection endpoints.

Instead of database IP addresses in connection strings, utilise aliases for database endpoints. This permits database migration without affecting applications because the connection string is not changed. The transferred Cloud SQL database’s alias simply needs updating.

Except for special needs, enterprise clients use private Cloud SQL instances. Cloud DNS may resolve FQDNs to Cloud SQL’s public or private IP address. Application settings can point to the SQL host record using the Cloud DNS name. After migration, only the Cloud DNS record for the moved Cloud SQL instance has to be updated.

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