Databases (ENY) Flashcards
If I launch a standby RDS instance, will it be in the same Availability Zone as my primary? A. Only for Oracle RDS types B. Yes C. Only if it is configured at launch D. No
Answer D.
Explanation: No. The purpose of having a standby instance is to avoid an infrastructure failure (if it happens), therefore the standby instance is stored in a different availability zone, which is a physically different independent infrastructure.
When would I prefer Provisioned IOPS over Standard RDS storage?
A. If you have batch-oriented workloads
B. If you use production online transaction processing (OLTP) workloads.
C. If you have workloads that are not sensitive to consistent performance
D. All of the above
Answer A.
Explanation: Provisioned IOPS deliver high IO rates but it is expensive as well. Batch processing workloads do not require manual intervention they enable full utilization of systems, therefore a provisioned IOPS will be preferred for batch-oriented workload.
How is Amazon RDS, DynamoDB and Redshift different?
Amazon RDS is a database management service for relational databases, it manages patching, upgrading, backing up of data etc. of databases for you without your intervention. RDS is a Db management service for structured data only.
DynamoDB, on the other hand, is a NoSQL database service, NoSQL deals with unstructured data.
Redshift, is an entirely different service, it is a data warehouse product and is used in data analysis.
If I am running my DB Instance as a Multi-AZ deployment, can I use the standby DB Instance for read or write operations along with primary DB instance? A. Yes B. Only with MySQL based RDS C. Only for Oracle RDS instances D. No
Answer D.
Explanation: No, Standby DB instance cannot be used with primary DB instance in parallel, as the former is solely used for standby purposes, it cannot be used unless the primary instance goes down.
Your company’s branch offices are all over the world. They use a software with a multi-regional deployment on AWS and they use MySQL 5.6 for data persistence.
The task is to run an hourly batch process and read data from every region to compute cross-regional reports which will be distributed to all the branches. This should be done in the shortest time possible. How will you build the DB architecture in order to meet the requirements?
A. For each regional deployment, use RDS MySQL with a master in the region and a read replica in the HQ region
B. For each regional deployment, use MySQL on EC2 with a master in the region and send hourly EBS snapshots to the HQ region
C. For each regional deployment, use RDS MySQL with a master in the region and send hourly RDS snapshots to the HQ region
D. For each regional deployment, use MySQL on EC2 with a master in the region and use S3 to copy data files hourly to the HQ region
Answer A.
Explanation: For this we will take an RDS instance as a master, because it will manage our database for us and since we have to read from every region, we’ll put a read replica of this instance in every region where the data has to be read from. Option C is not correct since putting a read replica would be more efficient than putting a snapshot, a read replica can be promoted if needed to an independent DB instance, but with a Db snapshot it becomes mandatory to launch a separate DB Instance.
Can I run more than one DB instance for Amazon RDS for free?
Yes. You can run more than one Single-AZ Micro database instance, that too for free! However, any use exceeding 750 instance hours, across all Amazon RDS Single-AZ Micro DB instances, across all eligible database engines and regions, will be billed at standard Amazon RDS prices. For example: if you run two Single-AZ Micro DB instances for 400 hours each in a single month, you will accumulate 800 instance hours of usage, of which 750 hours will be free. You will be billed for the remaining 50 hours at the standard Amazon RDS price.
Which AWS services will you use to collect and process e-commerce data for near real-time analysis? Select all that apply. A. Amazon ElastiCache B. Amazon DynamoDB C. Amazon Redshift D. Amazon Elastic MapReduce
Answer B,C.
Explanation: DynamoDB is a fully managed NoSQL database service. DynamoDB, therefore can be fed any type of unstructured data, which can be data from e-commerce websites as well, and later, an analysis can be done on them using Amazon Redshift. We are not using Elastic MapReduce, since a near real time analyses is needed.
Can I retrieve only a specific element of the data, if I have a nested JSON data in DynamoDB?
Yes. When using the GetItem, BatchGetItem, Query or Scan APIs, you can define a Projection Expression to determine which attributes should be retrieved from the table. Those attributes can include scalars, sets, or elements of a JSON document.
A company is deploying a new two-tier web application in AWS. The company has limited staff and requires high availability, and the application requires complex queries and table joins. Which configuration provides the solution for the company’s requirements?
A. MySQL Installed on two Amazon EC2 Instances in a single Availability Zone
B. Amazon RDS for MySQL with Multi-AZ
C. Amazon ElastiCache
D. Amazon DynamoDB
Answer D.
Explanation: DynamoDB has the ability to scale more than RDS or any other relational database service, therefore DynamoDB would be the apt choice.
What happens to my backups and DB Snapshots if I delete my DB Instance?
When you delete a DB instance, you have an option of creating a final DB snapshot, if you do that you can restore your database from that snapshot. RDS retains this user-created DB snapshot along with all other manually created DB snapshots after the instance is deleted, also automated backups are deleted and only manually created DB Snapshots are retained.
Which of the following use cases are suitable for Amazon DynamoDB?Choose 2 answers
A. Managing web sessions.
B. Storing JSON documents.
C. Storing metadata for Amazon S3 objects.
D. Running relational joins and complex updates.
Answer C,D.
Explanation: If all your JSON data have the same fields eg [id,name,age] then it would be better to store it in a relational database, the metadata on the other hand is unstructured, also running relational joins or complex updates would work on DynamoDB as well.
In RDS what is the maximum size for a Microsoft SQL Server DB Instance with SQL Server Express edition?
A) 10Gb per Database
B) 300Gb per Database
C) 1Tb per Database
D) 2Tb per Database
Answer: B
Explanation: The maximum storage size for a Microsoft SQL Server DB Instance is 4 TB for all instances except the SQL Server Express edition, which limits storage to a total of 300 GB.
Which AWS service is ideal for Business Intelligence//Data Warehousing? A. DynamoDB B. ElastiCache C. Redshift D. Elastic Beanstalk
Answer: C
When you add a rule to an RDS security group, you must specify a port number or protocol.
A. False
B. True
Answer: A
Explanation: You don’t need to specify a destination port number when you create DB security group rules. The port number defined for the DB instance is used as the destination port number for all rules defined for the DB security group. DB security groups can be created using the Amazon RDS API actions or the Amazon RDS page of the AWS Management Console.The port number defined for the DB instance is used as the destination port number for all rules defined for the DB security group.
What happens to the I/O operations of a single-AZ RDS instance during a database snapshot or backup?
A. I/O may be briefly suspended while the backup process initializes and you may experience a brief period of extended latency
B. Nothing
C. I/O operations to the database are sent to a secondary instance of a multi-AZ instance (for the duration of the snapshot)
D. I/O operations will function normally
Answer: A
Explanation: Amazon RDS creates a storage volume snapshot of your DB instance, backing up the entire DB instance and not just individual databases. Creating this DB snapshot on a Single-AZ DB instance results in a brief I/O suspension that can last from a few seconds to a few minutes, depending on the size and class of your DB instance. Multi-AZ DB instances are not affected by this I/O suspension since the backup is taken on the standby.
