Exam Professional Cloud Database Engineer topic 1 question 29 discussion

Actual exam question from Google's Professional Cloud Database Engineer

Question #: 29
Topic #: 1

[All Professional Cloud Database Engineer Questions]

Your company is migrating the existing infrastructure for a highly transactional application to Google Cloud. You have several databases in a MySQL database instance and need to decide how to transfer the data to Cloud SQL. You need to minimize the downtime for the migration of your 500 GB instance. What should you do?

A. 1. Create a Cloud SQL for MySQL instance for your databases, and configure Datastream to stream your database changes to Cloud SQL.
2. Select the Backfill historical data check box on your stream configuration to initiate Datastream to backfill any data that is out of sync between the source and destination.
3. Delete your stream when all changes are moved to Cloud SQL for MySQL, and update your application to use the new instance.
B. 1. Create migration job using Database Migration Service.
2. Set the migration job type to Continuous, and allow the databases to complete the full dump phase and start sending data in change data capture (CDC) mode.
3. Wait for the replication delay to minimize, initiate a promotion of the new Cloud SQL instance, and wait for the migration job to complete.
4. Update your application connections to the new instance.
C. 1. Create migration job using Database Migration Service.
2. Set the migration job type to One-time, and perform this migration during a maintenance window.
3. Stop all write workloads to the source database and initiate the dump. Wait for the dump to be loaded into the Cloud SQL destination database and the destination database to be promoted to the primary database.
4. Update your application connections to the new instance.
D. 1. Use the mysqldump utility to manually initiate a backup of MySQL during the application maintenance window.
2. Move the files to Cloud Storage, and import each database into your Cloud SQL instance.
3. Continue to dump each database until all the databases are migrated.
4. Update your application connections to the new instance.

Show Suggested Answer

Suggested Answer: B 🗳️

by Kloudgeek at Dec. 20, 2022, 9:37 p.m.

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dynamic_dba

Highly Voted 1 year, 9 months ago

B. A is wrong because Datastream is a CDC and replication service for data synchronization across heterogeneous databases. It’s reasonable to assume you’ll be using Cloud SQL for MySQL, so you’ll be performing a homogeneous migration. Plus, while the a Datastream source can be MySQL, a Datastream target is either BigQuery or Cloud Storage and not Cloud SQL. See https://cloud.google.com/datastream/docs/overview. C is wrong because a one time migration wouldn’t capture all the data changes once the maintenance window ended and the apps were fired back up. Furthermore, stopping all writes during the dump would constitute downtime which the question wants minimized. D would take forever in a rapidly changing source system. B is the cleanest and simplest solution especially since the question puts no time constraint on making the migration happen.

upvoted 8 times

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887ad17

Most Recent 4 months, 3 weeks ago

Selected Answer: B

only B have initiate a promotion of the new Cloud SQL instance

upvoted 1 times

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dija123

6 months, 4 weeks ago

Selected Answer: B

Agree with B

upvoted 1 times

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Pilot50

1 year, 8 months ago

Selected Answer: B

C isn't correct since it will not minimize the downtime

upvoted 2 times

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Nirca

1 year, 9 months ago

Selected Answer: B

B is the correct answer

upvoted 1 times

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pk349

1 year, 11 months ago

B: Create migration job using Database ***** Migration Service. Set the migration job type to Continuous, and allow the databases to complete the full dump phase and start sending data in change data capture (CDC) mode. Wait ***** for the replication delay to minimize, initiate a promotion of the new Cloud SQL instance, and wait for the migration job to complete. Update your application connections to the new instance.

upvoted 1 times

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