Alibaba Alibaba Certifications ACA-DATABASE Questions & Answers

• Question 61:

  Which of the following is the wrong statement about PolarDB design architecture?

  A. A PolarDB cluster contains one primary instance and up to 15 read-only instances

  B. PolarDB consolidate compute processes and storage processes in one box, allowing the database capacity to scale up and down to meet your application needs in Alibaba Cloud

  C. Read/write splitting is enabled for PolarDB clusters by default, providing transparent, highly available, and self-adaptive load balancing for your database

  D. High speed network connection is enabled between the DB server and the chunk server, and data are transferred using the Remote Direct Memory Access (RDMA) protocol

  Correct Answer: B

  PolarDB decouples compute from storage. https://www.alibabacloud.com/help/doc-detail/58766.htm?spm=a2c63.p38356.b99.11.4e333181dMpFmV

• Question 62:

  Which of the following statements about MongoDB is NOT true?

  A. MongoDB is a relational database.

  B. MongoDB is a document database.

  C. MongoDB supports transactions.

  D. MongoDB can be deployed in cluster mode.

  Correct Answer: A

• Question 63:

  PolarDB for MySQL archive databases use log-structured merge-trees (LSM trees) and the Zstandard (ZSTD) data compression algorithm to increase the data compression ratio. How much storage can be saved, at most?

  A. 40%

  B. 50%

  C. 60%

  D. 70%

  Correct Answer: D

• Question 64:

  Which of the following features are provided by PolarDB-O's proxy? (Number of correct

  A. Read/write splitting

  B. Load balancing

  C. Health checks for nodes

  D. Failover strategies for high availability

  E. Data encryption

  Correct Answer: ABCD

• Question 65:

  PolarDB for MySQL allows you to deploy a cluster across multiple zones. Compared with single-zone clusters, multi-zone clusters have better disaster recovery capabilities and can withstand data centre-level faults.

  A. True

  B. False

  Correct Answer: A

  Compared with single-zone clusters, multi-zone clusters can enhance disaster recovery capabilities and withstand the breakdown of an entire data center. https://www.alibabacloud.com/help/doc-detail/122182.htm?spm=a2c63.p38356.879954.4.6f2fa25362cz60#task-1580301

• Question 66:

  Which of the following is not a feature or usage scenario of Data Lake Analytics (DLA)?

  A. Interactive analysis

  B. Batch processing

  C. Online transaction processing

  D. Stream or micro-batch processing

  Correct Answer: C

• Question 67:

  Which of the following are the core technologies behind Database Backup Service? (Number of correct answers: 3)

  A. Multi-cloud and multi-backend backup

  B. Real-time synchronization

  C. High mount speeds (a few seconds)

  D. Online query and analysis

  Correct Answer: ABC

• Question 68:

  Your DTS (Data Transmission Service) migration has failed halfway through: what options do you have? (Number of correct answers: 2)

  A. Delete your DTS instance and start over

  B. Restart the migration task from the console

  C. Your database can't be migrated: you need to abandon the migration

  D. You need to switch to ADAM, as DTS cannot complete the migration

  Correct Answer: BD

• Question 69:

  If a database exception occurs in a PolarDB cluster because important data is deleted by mistake, how i can data be restored?

  A. Level-2 backup + Redo log

  B. Level 1 backup + Redo log

  C. Level-2 backup

  D. Level-1 backup

  Correct Answer: A

• Question 70:

  Which of the following is the lowest recovery point objective (RPO) for Database Backup Service?

  A. Seconds

  B. Minutes

  C. Hours

  D. Days

  Correct Answer: B