Monday, October 17, 2016

AWS SAA Study List - RDS

RDS

Basics

  • Managed service (no SSH)
  • Supports Multi-AZ configurations
  • Supports MySQL, MariaDB, AuroraDB, Postgres, Oracle and MSSQL
  • Parameters of DB Instances are handled by parameter file (think Oracle spfile)
  • Offers automated backups
  • Backup storage for active databases is free
  • Databases can be restored within 5 minute timeframe (transaction logs are taken often)
  • Price is based on data in or out of your RDS into Internet (inside AWS free)

Limits

  • Storage limited from 5GB to 6TB
  • Backup window from 0 to 35


Following topics are exam questions collected through Internet and should be evaluated as so. Answers are mine and have been checked with answers collected through the internet, but might still be wrong.


Your company is getting ready to do a major public announcement of a social media site on AWS. The website is running on EC2 instances deployed across multiple Availability Zones with a Multi-AZ RDS MySQL Extra Large DB Instance. The site performs a high number of small reads and writes per second and relies on an eventual consistency model. After comprehensive tests you discover that there is read contention on RDS MySQL. Which are the best approaches to meet these requirements? (Choose 2 answers)

A. Deploy ElasticCache in-memory cache running in each availability zone
B. Implement sharding to distribute load to multiple RDS MySQL instances
C. Increase the RDS MySQL Instance size and Implement provisioned IOPS
D. Add an RDS MySQL read replica in each availability zone

Why? 'read contention' is the keyword, hence A and D are only ones which fullfil this requirement



A company is running a batch analysis every hour on their main transactional DB running on an RDS MySQL instance to populate their central Data Warehouse running on Redshift. During the execution of the batch their transactional applications are very slow. When the batch completes they need to update the top management dashboard with the new data. The dashboard is produced by another system running on-premises that is currently started when a manually-sent email notifies that an update is required. The on-premises system cannot be modified because is managed by another team. How would you optimize this scenario to solve performance issues and automate the process as much as possible?

A. Replace RDS with Redshift for the batch analysis and SNS to notify the on-premises system to update the dashboard
B. Replace RDS with Redshift for the batch analysis and SQS to send a message to the on-premises system to update the dashboard
C. Create an RDS Read Replica for the batch analysis and SNS to notify me on-premises system to update the dashboard
D. Create an RDS Read Replica for the batch analysis and SQS to send a message to the on-premises system to update the dashboard.

Why? Ruling out the SQS options first, leaves us A and C. Read replica would solve the case easiest, hence C.



Will my standby RDS instance be in the same Availability Zone as my primary?
A. Only for Oracle RDS types
B. Yes
C. Only if configured at launch
D. No

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html "In a Multi-AZ deployment, Amazon RDS automatically provisions and maintains a synchronous standby replica in a different Availability Zone."



Is creating a Read Replica of another Read Replica supported?
A. Only in certain regions
B. Only with MySQL based RDS
C. Only for Oracle RDS types
D. No

Why? https://aws.amazon.com/about-aws/whats-new/2013/08/28/amazon-rds-read-replica-new-features/ "Create a replica from an existing Read Replica (supported for MySQL 5.6) - You can now create a second-tier Read Replica from an existing first-tier Read Replica."



A user is planning to set up the Multi-AZ feature of RDS. Which of the below mentioned conditions won’t take advantage of the Multi-AZ feature?
A. Availability zone outage
B. A manual failover of the DB instance using Reboot with failover option
C. Region outage
D. When the user changes the DB instance’s server type

Why? Multi-AZ uses the same region, hence if the region goes down, all the AZ's go down as well.



When you run a DB Instance as a Multi-AZ deployment, the “_____” serves database writes and reads
A. Secondary
B. backup
C. stand by
D. primary

Why? Primary database is the starting point always.



When running my DB Instance as a Multi-AZ deployment, can I use the standby for read or write operations?
A. Yes
B. Only with MSSQL based RDS
C. Only for Oracle RDS instances
D. No

Why? Standby databases can't be used for write operations at all, no matter which technology.



Read Replicas require a transactional storage engine and are only supported for the _________ storage engine
A. OracleISAM
B. MSSQLDB
C. InnoDB
D. MyISAM

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html "Replication is only supported for the InnoDB storage engine on MySQL and the XtraDB storage engine on MariaDB."



A user is configuring the Multi AZ feature of an RDS DB. The user came to know that this RDS DB does not use the AWS technology, but uses server mirroring to achieve replication. Which DB is the user using right now?
A. MySQL
B. Oracle
C. MSSQL
D. PostgreSQL

Why? https://msdn.microsoft.com/en-us/library/ms189852.aspx Database Mirroring (SQL Server)



If I have multiple Read Replicas for my master DB Instance and I promote one of them, what happens to the rest of the Read Replicas?
A. The remaining Read Replicas will still replicate from the older master DB Instance
B. The remaining Read Replicas will be deleted
C. The remaining Read Replicas will be combined to one read replica

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html "If you promote a MySQL or MariaDB Read Replica that is in turn replicating to other Read Replicas, those Read Replicas remain active. Consider an example where MyDBInstance1 replicates to MyDBInstance2, and MyDBInstance2 replicates to MyDBInstance3. If you promote MyDBInstance2, replication from MyDBInstance1 to MyDBInstance2 no longer occurs, but MyDBInstance2 still replicates to MyDBInstance3."



If you have chosen Multi-AZ deployment, in the event of a planned or unplanned outage of your primary DB Instance, Amazon RDS automatically switches to the standby replica. The automatic failover mechanism simply changes the ______ record of the main DB Instance to point to the standby DB Instance.
A. DNAME
B. CNAME
C. TXT
D. MX

Why? https://aws.amazon.com/blogs/aws/amazon-rds-multi-az-deployment/ "The CNAME record for your DB instance will be altered to point to the newly promoted standby."



When automatic failover occurs, Amazon RDS will emit a DB Instance event to inform you that automatic failover occurred. You can use the _____ to return information about events related to your DB Instance
A. FetchFailure
B. DescribeFailure
C. DescribeEvents
D. FetchEvents

Why? http://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_DescribeEvents.html "Returns events related to DB instances, DB security groups, DB snapshots, and DB parameter groups for the past 14 days. Events specific to a particular DB instance, DB security group, database snapshot, or DB parameter group can be obtained by providing the name as a parameter. By default, the past hour of events are returned."


The new DB Instance that is created when you promote a Read Replica retains the backup window period.
A. TRUE
B. FALSE

Why? http://docs.aws.amazon.com/AmazonRDS/latest/CommandLineReference/CLIReference-cmd-PromoteRead.html "We recommend that you enable automated backups on your Read Replica before promoting the Read Replica. This ensures that no backup is taken during the promotion process. Once the instance is promoted to a primary instance, backups are taken based on your backup settings."



Will I be alerted when automatic failover occurs?
A. Only if SNS configured
B. No
C. Yes
D. Only if Cloudwatch configured

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html "DB event subscriptions can be setup to notify you via email or SMS that a failover has been initiated. For more information about events, see Using Amazon RDS Event Notification"



Can I initiate a “forced failover” for my MySQL Multi-AZ DB Instance deployment?
A. Only in certain regions
B. Only in VPC
C. Yes
D. No

Why? Yes, of course no matter of region or VPC configuration.


A user is accessing RDS from an application. The user has enabled the Multi-AZ feature with the MS SQL RDS DB. During a planned outage how will AWS ensure that a switch from DB to a standby replica will not affect access to the application?
A. RDS will have an internal IP which will redirect all requests to the new DB
B. RDS uses DNS to switch over to standby replica for seamless transition
C. The switch over changes hardware so RDS does not need to worry about access
D. RDS will have both the DBs running independently and the user has to manually switch over

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html "The primary DB instance switches over automatically to the standby replica if any of the following conditions occur: The operating system of the DB instance is undergoing software patching"



Which of the following is part of the failover process for a Multi-Availability Zone Amazon Relational Database Service (RDS) instance?
A. The failed RDS DB instance reboots.
B. The IP of the primary DB instance is switched to the standby DB instance.
C. The DNS record for the RDS endpoint is changed from primary to standby.
D. A new DB instance is created in the standby availability zone.

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html "The failover mechanism automatically changes the DNS record of the DB instance to point to the standby DB instance."


True or False: When you perform a restore operation to a point in time or from a DB Snapshot, a new DB Instance is created with a new endpoint.

A. FALSE
B. TRUE

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_RestoreFromSnapshot.html "You cannot restore from a DB snapshot to an existing DB instance; a new DB instance is created when you restore."


Because of the extensibility limitations of striped storage attached to Windows Server, Amazon RDS does not currently support increasing storage on a DB Instance.

A. SQL Server
B. MySQL
C. Oracle

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_SQLServer.html "Because of the extensibility limitations of striped storage attached to Windows Server, Amazon RDS does not currently support increasing storage on a SQL Server DB Instance."


If I modify a DB Instance or the DB parameter group associated with the instance, should I
reboot the instance for the changes to take effect?

A. No
B. Yes

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_RebootInstance.html "In some cases, if you modify a DB instance, change the DB parameter group associated with the instance, or change a static DB parameter in a parameter group the instances uses, you must reboot the instance for the changes to take effect."


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

Why? B instead of A, as "limited staff" is mentioned and RDS is fully managed service. Complex queries and table joins point to RDS.


You are running a successful multitier web application on AWS and your marketing department has asked you to add a reporting tier to the application. The reporting tier will aggregate and publish status reports every 30 minutes from user-generated information that is being stored in your web application s database. You are currently running a Multi-AZ RDS MySQL instance for the database tier. You also have implemented Elasticache as a database caching layer between the application tier and database tier. Please select the answer that will allow you to successfully implement the reporting tier with as little impact as possible to your database.

A. Continually send transaction logs from your master database to an S3 bucket and generate the reports off the S3 bucket using S3 byte range requests.
B. Generate the reports by querying the synchronously replicated standby RDS MySQL instance maintained through Multi-AZ.
C. Launch a RDS Read Replica connected to your Multi AZ master database and generate reports by querying the Read Replica.
D. Generate the reports by querying the ElastiCache database caching tier.

Why? MySQL supports Read Replica, which provides readable database for realtime reporting.


Will my standby RDS instance be in the same Region as my primary?

A. Only for Oracle RDS types
B. Yes
C. Only if configured at launch
D. No

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html "In a Multi-AZ deployment, Amazon RDS automatically provisions and maintains a synchronous standby replica in a different Availability Zone."


True or False: When using IAM to control access to your RDS resources, the key names that can be used are case sensitive. For example, aws:CurrentTime is NOT equivalent to AWS:currenttime.

A. TRUE
B. FALSE

Why http://docs.aws.amazon.com/directconnect/latest/UserGuide/using_iam.html "Key names are case-insensitive. For example, aws:CurrentTime is equivalent to AWS:currenttime."

http://docs.aws.amazon.com/IAM/latest/UserGuide/reference_policies_elements.html "The name must match an action that is supported by the service. The prefix and the action name are case insensitive. For example, iam:ListAccessKeys is the same as IAM:listaccesskeys."


True or False: Automated backups are enabled by default for a new DB Instance.

A. TRUE
B. FALSE

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Overview.BackingUpAndRestoringAmazonRDSInstances.html "Automated backup is an Amazon RDS feature that automatically creates a backup of your DB instance. Automated backups are enabled by default for a new DB instance."


Amazon RDS automated backups and DB Snapshots are currently supported for only the __________ storage engine

A. InnoDB
B. MyISAM

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Overview.BackingUpAndRestoringAmazonRDSInstances.html "Amazon RDS automated backups and DB snapshots are currently supported for all DB engines. For the MySQL DB engine, only the InnoDB storage engine is supported; use of these features with other MySQL storage engines, including MyISAM, may lead to unreliable behavior while restoring from backups."


Typically, you want your application to check whether a request generated an error before you spend any time processing results. The easiest way to find out if an error occurred is to look for an __________ node in the response from the Amazon RDS API.

A. Incorrect
B. Error
C. FALSE

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/APITroubleshooting.html "Typically, you want your application to check whether a request generated an error before you spend any time processing results. The easiest way to find out if an error occurred is to look for an Error node in the response from the Amazon RDS API."


In the Amazon CloudWatch, which metric should I be checking to ensure that your DB Instance has enough free storage space?

A. FreeStorage
B. FreeStorageSpace
C. FreeStorageVolume
D. FreeDBStorageSpace

Why? http://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/rds-metricscollected.html "FreeStorageSpace The amount of available storage space."


Amazon RDS DB snapshots and automated backups are stored in

A. Amazon S3
B. Amazon ECS Volume
C. Amazon RDS
D. Amazon EMR

Why? https://aws.amazon.com/rds/faqs/ "Where are my automated backups and DB Snapshots stored and how do I manage their retention?: Amazon RDS DB snapshots and automated backups are stored in S3."


You must increase DB storage size in increments of at least _____ %

A. 40
B. 20
C. 50
D. 10

Why? http://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ModifyDBInstance.html "AllocatedStorage Constraints: Value supplied must be at least 10% greater than the current value."


Changes to the backup window take effect ______.

A. from the next billing cycle
B. after 30 minutes
C. immediately
D. after 24 hours

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Overview.BackingUpAndRestoringAmazonRDSInstances.html "Changes to the backup window take effect immediately. The backup window cannot overlap with the weekly maintenance window for the DB instance."


What are the two types of licensing options available for using Amazon RDS for Oracle?

A. BYOL and Enterprise License
B. BYOL and License Included
C. Enterprise License and License Included
D. Role based License and License Included

Why? https://aws.amazon.com/rds/oracle/ "You can run Amazon RDS for Oracle under two different licensing models – “License Included” and “Bring-Your-Own-License (BYOL)”."


Disabling automated backups ______ disable the point-in-time recovery.

A. if configured to can
B. will never
C. will

Why? This doesn't need explaining


True or False: Manually created DB Snapshots are deleted after the DB Instance is deleted.

A. TRUE
B. FALSE

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_DeleteInstance.html "Manual DB snapshots of the instance are not deleted."


Is Federated Storage Engine currently supported by Amazon RDS for MySQL?

A. Only for Oracle RDS instances
B. No
C. Yes
D. Only in VPC

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_MySQL.html "The Federated Storage Engine is currently not supported by Amazon RDS for MySQL."


What happens to the I/O operations while you take a database snapshot?

A. I/O operations to the database are suspended for a few minutes while the backup is in progress.
B. I/O operations to the database are sent to a Replica (if available) for a few minutes while the backup is in  progress.
C. I/O operations will be functioning normally
D. I/O operations to the database are suspended for an hour while the backup is in progress

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_CreateSnapshot.html "Creating this DB snapshot on a Single-AZ DB instance results in a brief I/O suspension that typically lasting no more than a few minutes."


When should I choose 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

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_Storage.html "Provisioned IOPS storage is designed to meet the needs of I/O-intensive workloads, particularly database workloads, that are sensitive to storage performance and consistency in random access I/O throughput."


True or False: If you add a tag that has the same key as an existing tag on a DB Instance, the new value overwrites the old value.

A. FALSE
B. TRUE


Why? http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Using_Tags.html "If you add a tag that has the same key as an existing tag on that resource, the new value overwrites the old value."


Are Reserved Instances available for Multi-AZ Deployments?

A. Only for Cluster Compute instances
B. Yes for all instance types
C. Only for M3 instance types
D. No

Why? https://aws.amazon.com/rds/faqs/ "Are Reserved Instances available for Multi-AZ Deployments?: Yes. When you call the DescribeReservedDBInstancesOfferings API or describe-reserved-db-instances-offerings command, simply look for the Multi-AZ options listed among the DB Instance configurations available for purchase. If you want to purchase a reservation for a DB Instance with synchronous replication across multiple Availability Zones, specify one of these offerings in your PurchaseReservedDBInstancesOffering call."


When automatic failover occurs, Amazon RDS will emit a DB Instance event to inform you that automatic failover occurred. You can use the _____ to return information about events related to your DB Instance

A. FetchFailure
B. DescribeFailure
C. DescribeEvents
D. FetchEvents

Why? https://aws.amazon.com/rds/faqs/ "Q: Will I be alerted when automatic failover occurs?: Yes, Amazon RDS will emit a DB Instance event to inform you that automatic failover occurred. You can click the “Events” section of the Amazon RDS Console or use the DescribeEvents API to return information about events related to your DB Instance. You can also use Amazon RDS Event Notifications to be notified when specific DB events occur."


Is the SQL Server Audit feature supported in the Amazon RDS SQL Server engine?

A. No
B. Yes

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_SQLServer.html
Amazon RDS currently does not support the following SQL Server features: SQL Server Audit


If your DB instance runs out of storage space or file system resources, its status will change to_____ and your DB Instance will no longer be available.

A. storage-overflow
B. storage-full
C. storage-exceed
D. storage-overage

Why? https://aws.amazon.com/ko/premiumsupport/knowledge-center/rds-out-of-storage/ "When an RDS DB instance reaches the STORAGE_FULL state, there is not enough space available for performing basic operations, eventually preventing you to make connections or restart the instance."


Does Amazon RDS for SQL Server currently support importing data into the msdb database?

A. No
B. Yes

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_SQLServer.html "Amazon RDS for SQL Server does not support importing data into the msdb database."


Is decreasing the storage size of a DB Instance permitted?

A. Depends on the RDMS used
B. Yes
C. No

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_Storage.html#CHAP_Storage.FactsAbout "You cannot decrease storage allocated for a DB instance."


In the context of MySQL, version numbers are organized as MySQL version = X.Y.Z. What does X denote here?

A. release level
B. minor version
C. version number
D. major version

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_MySQL.html "MySQL, version numbers are organized as version = X.Y.Z. In Amazon RDS terminology, X.Y denotes the major version, and Z is the minor version number."


Do the system resources on the Micro instance meet the recommended configuration for Oracle?

A. Yes completely
B. Yes but only for certain situations
C. Not in any circumstance

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.DBInstanceClass.html#Concepts.DBInstanceClass.Previous "Micro Instances (db.t1.micro) are instances sufficient for testing that should not be used for production applications. Using a db.t1.micro instance with Oracle is a limited test configuration. If you want to use a micro DB instance class, the db.t1.micro DB instance class only supports Oracle versions 11.2.0.2, 11.2.0.3, and 12.1.0.1. PostgreSQL version 9.5.2 does not support this instance class."


True or False: When you add a rule to a DB security group, you do not need to specify port number or protocol.

A. Depends on the RDMS used
B. TRUE
C. FALSE

http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Overview.RDSSecurityGroups.html
"You do not 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."


Amazon RDS creates an SSL certificate and installs the certificate on the DB Instance when Amazon RDS provisions the instance. These certificates are signed by a certificate authority. The _____ is stored at https://rds.amazonaws.com/doc/rds-ssl-ca-cert.pem.

A. private key
B. foreign key
C. public key
D. protected key

Why? https://aws.amazon.com/blogs/aws/amazon-rds-sql-server-ssl-support/ "Download a public certificate key from RDS at https://rds.amazonaws.com/doc/rds-ssl-ca-cert.pem"


If I scale the storage capacity provisioned to my DB Instance by mid of a billing month, how will I be charged?

A. You will be charged for the highest storage capacity you have used
B. On a proration basis
C. You will be charged for the lowest storage capacity you have used

Why? https://aws.amazon.com/rds/faqs/ "Storage (per GB per month) – Storage capacity you have provisioned to your DB Instance. If you scale your provisioned storage capacity within the month, your bill will be pro-rated."

Amazon RDS supports SOAP only through __________.

A. HTTP or HTTPS
B. TCP/IP
C. HTTP
D. HTTPS

Why? http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/using-soap-api.html "Amazon RDS supports SOAP only through HTTPS."


A company wants to implement their website in a virtual private cloud (VPC). The web tier will use an Auto Scaling group across multiple Availability Zones (AZs). The database will use Multi-AZ RDS MySQL and should not be publicly accessible. What is the minimum number of subnets that need to be configured in the VPC?

A. 1
B. 2
C. 3
D. 4

Why? You can have your Web servers in two VPC's and configure the RDS servers to use those as well. You just need to configure RDS to be "not publicly accessible" to fullfil the needs of this scenario.

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