DBS-C01 Management and Operations Practice Test 15 — 15 Questions

Question 1

A developer accidentally deleted a production RDS for PostgreSQL DB instance. The company has automated backups enabled with a retention period of 7 days. What is the fastest way to restore the database to the state just before the deletion?

Accepted Answer

Create a new DB instance and use point-in-time recovery to the time just before deletion.. Option C is correct. When automated backups are enabled, you can restore a DB instance to any point within the retention period, even after deletion. The deleted instance is retained for the backup retention period. Option A is wrong because point-in-time recovery does not require a manual snapshot. Option B is wrong because a manual snapshot was not taken. Option D is wrong because you cannot recover from the Recycle Bin for RDS instances; RDS does not use the Recycle Bin.

Answer

Recover the instance from the Amazon RDS Recycle Bin.

Answer

Restore from the latest automated snapshot that was taken before deletion.

Answer

Use the AWS DMS to migrate the data from the deleted instance to a new one.

Question 2

A company runs an Amazon RDS for MySQL Multi-AZ DB instance. The application experiences intermittent read latency spikes. The DB instance type is db.r5.large with 500 GB of General Purpose SSD (gp2) storage. The spike occurs during peak hours when read activity is high. Which action would most effectively reduce read latency?

Accepted Answer

Create an Amazon RDS read replica and direct read traffic to it.. Option D is correct. Adding a read replica offloads read traffic from the primary instance, reducing latency. Option A is wrong because Multi-AZ does not improve read performance; the standby is not used for reads. Option B is wrong because increasing storage may improve throughput but not resolve read contention. Option C is wrong because gp3 provides consistent performance but does not solve read scaling.

Answer

Change the storage type to Provisioned IOPS (io1).

Answer

Enable Multi-AZ with a standby replica.

Answer

Increase the allocated storage to 1 TB to improve IOPS.

Question 3

Refer to the exhibit. An Amazon RDS for Oracle instance is experiencing ORA-00257 errors. The DBA has already increased the archive log retention setting. What is the most efficient next step to resolve the issue without manual intervention?

Accepted Answer

Modify the DB instance to increase the allocated storage.. Option C is correct. The error indicates the flash recovery area is full. The most efficient automated way is to modify the RDS DB instance to increase allocated storage, which also increases the recovery area. Option A is wrong because manually deleting logs is not automated. Option B is wrong because archiving to S3 is not a standard RDS feature. Option D is wrong because restarting does not free space.

Answer

Configure archiving to Amazon S3 to offload logs.

Answer

Reboot the DB instance to clear the recovery area.

Answer

Manually delete old archive logs from the recovery area using RMAN.

Question 4

A company is using Amazon DynamoDB with on-demand capacity. The application experiences increased latency during peak hours. The DynamoDB table receives about 5,000 writes per second and 10,000 reads per second. The read latency is high, but write latency is acceptable. What should the company do to reduce read latency?

Accepted Answer

Enable DynamoDB Accelerator (DAX) for the table.. Option A is correct. DynamoDB Accelerator (DAX) is a fully managed, highly available, in-memory cache that reduces read latency. Option B is wrong because auto scaling is for provisioned capacity, not on-demand. Option C is wrong because read replicas are not a DynamoDB feature. Option D is wrong because DynamoDB Streams does not cache data.

Answer

Enable DynamoDB Streams to offload read traffic.

Answer

Create a read replica of the DynamoDB table.

Answer

Switch to provisioned capacity and enable auto scaling.

Question 5

A company manages multiple RDS for PostgreSQL instances in different AWS accounts. The security team requires that all DB instances have automated backups enabled with a retention period of at least 14 days. How can the company enforce this policy across all accounts?

Accepted Answer

Use AWS Config rules to evaluate and auto-remediate non-compliant instances.. Option D is correct. AWS Config with managed rules can evaluate RDS instances and enforce backup settings. Option A is wrong because IAM policies cannot enforce backup settings on resources. Option B is wrong because CloudTrail does not enforce configuration. Option C is wrong because Service Control Policies (SCPs) are used for permissions at the organization level, not for resource configuration.

Answer

Use AWS CloudTrail to monitor backup settings and alert on non-compliance.

Answer

Apply a service control policy (SCP) that requires backup retention.

Answer

Create an IAM policy that denies creating DB instances without backup retention.

Question 6

Refer to the exhibit. An application on an EC2 instance is trying to read an object from the S3 bucket 'data-lake-prod'. The instance is in a VPC with an IP address of 10.0.1.5. The application receives an Access Denied error. What is the cause?

Accepted Answer

A Deny statement with a source IP condition is blocking access.. Option B is correct. The Deny statement applies to the source IP 10.0.1.5 (within 10.0.0.0/8), overriding the Allow. Option A is wrong because the IAM role does allow s3:GetObject on the bucket. Option C is wrong because there is no explicit condition on the Allow statement. Option D is wrong because the policy is attached to the role, not an SCP.

Answer

An SCP is denying S3 access to the account.

Answer

The S3 bucket policy requires a specific VPC endpoint.

Answer

The IAM role does not have permission to read from the bucket.

Question 7

A company is running an Amazon Aurora MySQL-compatible edition DB cluster. The application reports that a recent schema change caused a significant increase in the number of deadlocks. Which parameter should the DBA check and possibly adjust to reduce deadlocks?

Accepted Answer

innodb_lock_wait_timeout. Option C is correct. The innodb_lock_wait_timeout controls how long a transaction waits for a lock before rolling back. Reducing it can help avoid long waits, but deadlocks are often resolved by MySQL automatically; adjusting this parameter may not directly reduce deadlocks but can help. Actually, for deadlocks, the best practice is to examine the application logic. However, among the options, innodb_lock_wait_timeout is relevant. Option A is wrong because transaction isolation level affects concurrency but not deadlocks directly. Option B is wrong because max_connections is about connection count. Option D is wrong because autocommit affects transaction behavior.

Answer

autocommit

Answer

max_connections

Answer

transaction_isolation

Question 8

A company uses Amazon ElastiCache for Redis to cache frequently accessed data. The cache cluster experiences high CPU utilization during peak hours. The cluster has a single node of type cache.r5.large. What is the most cost-effective way to reduce CPU utilization while maintaining performance?

Accepted Answer

Add a read replica to distribute read traffic.. Option A is correct. Adding a read replica (sharing read traffic) reduces CPU on the primary. Option B is wrong because increasing to a larger node type is more expensive than adding replicas. Option C is wrong because increasing maxmemory-policy does not reduce CPU. Option D is wrong because enabling encryption adds overhead.

Answer

Enable encryption at rest and in transit.

Answer

Upgrade to a cache.r5.xlarge node type.

Answer

Increase the maxmemory-policy parameter to 'allkeys-lru'.

Question 9

A company's RDS for SQL Server instance has been running for 3 years. The DBA notices that the DB instance's allocated storage (500 GB) is 80% full. The application is write-heavy. The DBA needs to increase storage without downtime. What is the most efficient way to achieve this?

Accepted Answer

Use the Modify DB Instance API to increase allocated storage.. Option C is correct. RDS supports modifying storage without downtime for SQL Server if the storage type supports it. Option A is wrong because creating a new instance involves downtime. Option B is wrong because you cannot attach EBS directly to RDS. Option D is wrong because restoring from snapshot takes time and may require downtime.

Answer

Attach an additional EBS volume to the DB instance.

Answer

Create a new DB instance with larger storage and migrate data.

Answer

Take a snapshot and restore a new instance with larger storage.

Question 10

A company is using Amazon RDS for MySQL with Multi-AZ deployment. The DBA receives an alert that the standby replica is lagging behind the primary. Which TWO actions should the DBA take to investigate the issue? (Choose TWO.)

Accepted Answer

Verify network latency between the primary and standby.. Option A and Option C are correct. Option A checks the replication lag metric. Option C checks network latency, which can affect replication. Option B is wrong because Multi-AZ does not have read replicas. Option D is wrong because storage type does not directly cause lag. Option E is wrong because Multi-AZ uses synchronous replication, not async.

Answer

Check the 'Replica Lag' metric for any read replicas.

Answer

Increase the allocated storage to improve IOPS.

Answer

Change the replication type from asynchronous to synchronous.

Question 11

A company uses Amazon DynamoDB with provisioned capacity for a critical application. During a traffic spike, the table experiences throttling on write requests. The DBA needs to resolve the issue quickly. Which THREE actions should the DBA take? (Choose THREE.)

Accepted Answer

Implement exponential backoff in the application's write requests.. Option A, Option D, and Option E are correct. Option A increases write capacity immediately. Option D implements exponential backoff to handle throttling. Option E uses DynamoDB Auto Scaling to adjust capacity. Option B is wrong because DAX is for reads, not writes. Option C is wrong because switching to on-demand may cause higher costs and is not a quick fix for the spike.

Answer

Switch the table to on-demand capacity mode.

Answer

Enable DynamoDB Accelerator (DAX) to cache writes.

Question 12

A company is planning to migrate its on-premises Oracle database to Amazon RDS for Oracle. The database uses Oracle Data Guard for disaster recovery. Which TWO AWS services can be used to assess the database and plan the migration? (Choose TWO.)

Accepted Answer

AWS Database Migration Service (DMS). Option C and Option D are correct. AWS DMS can migrate the database, and AWS Schema Conversion Tool (SCT) can assess and convert the schema. Option A is wrong because CloudEndure is for server migration. Option B is wrong because AWS Migration Hub tracks migrations but does not assess databases. Option E is wrong because AWS Snowball is for large data transfer offline.

Answer

AWS Migration Hub

Answer

CloudEndure Disaster Recovery

Answer

AWS Snowball

Question 13

Refer to the exhibit. A DBA is checking the backup configuration of an RDS MySQL instance. The current time is 2023-03-15T06:00:00Z. What is the most recent point to which the database can be restored?

Accepted Answer

2023-03-15T04:30:00Z. Option C is correct. The latest restorable time is 2023-03-15T04:30:00Z, which is within the backup window. Option A is wrong because it is after the latest restorable time. Option B is wrong because it is earlier than the latest restorable time. Option D is wrong because the backup window ends at 06:00, but the latest restorable time is 04:30.

Answer

2023-03-15T03:00:00Z

Answer

2023-03-15T05:30:00Z

Answer

2023-03-15T06:00:00Z

Question 14

Refer to the exhibit. A DBA deploys this CloudFormation stack. After creation, the DBA needs to enable deletion protection for the DB instance. Which modification to the template would accomplish this?

Accepted Answer

Add 'DeletionProtection': true to the Properties.. Option D is correct. Adding DeletionProtection: true enables deletion protection. Option A is wrong because DeletionPolicy is a CloudFormation attribute, not a property. Option B is wrong because PreventRDSDeletion is not a valid property. Option C is wrong because the syntax is incorrect.

Answer

Add 'DeletionPolicy: Retain' to the resource.

Answer

Add 'PreventRDSDeletion: true' to the Properties.

Answer

Add 'DeletionProtection': 'Enabled' to the Properties.

Question 15

Refer to the exhibit. An RDS for PostgreSQL instance shows frequent checkpoints every 10 seconds. What is the most likely cause?

Accepted Answer

The 'max_wal_size' parameter is set too low, causing frequent WAL switches.. Option A is correct. Frequent checkpoints often indicate the log file size (max_wal_size) is too small, causing frequent WAL switches. Option B is wrong because full_storage? might cause issues but not specifically checkpoints. Option C is wrong because high connections may cause load but not checkpoints directly. Option D is wrong because autovacuum runs independently.

Answer

Autovacuum is not running, causing bloat.

Answer

The instance is running out of storage space.

Answer

There are too many concurrent connections.