RDS backup and snapshots in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ service_behavior

intermediate

RDS Automated Backups Retention Period

You have an Amazon RDS instance with automated backups enabled and a retention period set to 7 days. What happens to the automated backups if you delete the RDS instance?

A Automated backups remain indefinitely until manually deleted.

B Automated backups are retained for the retention period after deletion and then deleted automatically.

C Automated backups are converted to manual snapshots and retained indefinitely.

D All automated backups are deleted immediately when the instance is deleted.

💡 Hint

Think about what happens to automatic backups when the source instance no longer exists.

When you delete an RDS instance, all automated backups are deleted immediately. Only manual snapshots remain after deletion.

❓ Architecture

intermediate

Choosing Between Automated Backups and Manual Snapshots

You want to ensure daily backups of your RDS database that you can keep for 30 days and restore from any day within that period. Which approach should you use?

A Use manual snapshots only and keep them indefinitely.

B Enable automated backups with a 7-day retention and create manual snapshots weekly.

C Enable automated backups with a 30-day retention period.

D Create manual snapshots daily and delete them after 30 days.

💡 Hint

Consider which backup method supports automatic retention and point-in-time restore.

Automated backups with a 30-day retention allow point-in-time restore within that period. Manual snapshots do not support point-in-time restore and require manual management.

❓ security

advanced

Securing RDS Snapshots

You want to share an RDS manual snapshot with another AWS account but ensure the snapshot data is encrypted and secure. Which is the correct approach?

A Create a copy of the snapshot encrypted with a customer-managed KMS key and share the copy with the other account.

B Share the unencrypted manual snapshot directly with the other account.

C Enable automated backups and share the automated backup with the other account.

D Export the snapshot data to S3 and share the S3 bucket with the other account.

💡 Hint

Think about encryption and sharing permissions for snapshots.

Only manual snapshots can be shared. To share encrypted snapshots, you must create a copy encrypted with a customer-managed KMS key and share that key and snapshot with the other account.

✅ Best Practice

advanced

Optimizing RDS Backup Storage Costs

Your RDS instance has automated backups enabled with a 35-day retention period, but you notice high backup storage costs. What is the best way to reduce backup storage costs without losing the ability to restore to any point in the retention period?

A Enable backup compression on the RDS instance to reduce storage size.

B Reduce the automated backup retention period to 7 days and create manual snapshots weekly.

C Delete all manual snapshots to reduce storage costs.

D Use lifecycle policies to automatically delete older manual snapshots and keep automated backups.

💡 Hint

Consider how automated backups and manual snapshots affect storage costs and restore capabilities.

Automated backups with long retention increase storage costs. Reducing retention and supplementing with manual snapshots balances cost and restore needs.

🧠 Conceptual

expert

RDS Point-in-Time Restore Behavior

You have an RDS instance with automated backups enabled and a retention period of 10 days. You perform a point-in-time restore to a time 5 days ago. What is true about the restored instance?

A The restored instance contains data exactly as it was at the chosen time, including all transactions up to that point.

B The restored instance contains data only from the last manual snapshot before the chosen time.

C The restored instance contains data from the latest automated backup regardless of the chosen time.

D The restored instance contains data from the automated backup closest to the chosen time but may miss some transactions.

💡 Hint

Recall how point-in-time restore works with automated backups.

Point-in-time restore uses automated backups and transaction logs to restore the database to the exact state at the specified time, including all committed transactions.

Practice

1. What is the main difference between automated backups and manual snapshots in AWS RDS?

easy

A. Automated backups are stored outside AWS; manual snapshots are stored inside AWS.

B. Automated backups happen daily and expire; manual snapshots are created on demand and kept until deleted.

C. Automated backups are created only when the user requests; manual snapshots happen automatically every hour.

D. Automated backups cannot be restored; manual snapshots can only be viewed.

Solution

1. Step 1: Understand automated backups

   Automated backups run daily and keep data for a set retention period, after which they expire automatically.

2. Step 2: Understand manual snapshots

   Manual snapshots are created by the user anytime and remain until explicitly deleted.

3. Final Answer:

   Automated backups happen daily and expire; manual snapshots are created on demand and kept until deleted. -> Option B

4. Quick Check:

   Backup type difference = Automated expire, manual keep [OK]

Hint: Automated expire, manual keep until delete [OK]

Common Mistakes:

• Thinking manual snapshots expire automatically
• Believing automated backups are user-triggered only
• Confusing storage location of backups and snapshots

2. Which AWS CLI command correctly creates a manual snapshot of an RDS instance named mydbinstance?

easy

A. aws rds create-db-snapshot --db-instance-identifier mydbinstance --db-snapshot-identifier mydbsnapshot

B. aws rds backup-db-instance --instance mydbinstance --snapshot mydbsnapshot

C. aws rds snapshot-create --db-instance mydbinstance --snapshot-name mydbsnapshot

D. aws rds make-snapshot --db-instance-id mydbinstance --snapshot-id mydbsnapshot

Solution

1. Step 1: Identify correct AWS CLI syntax

   The correct command to create a manual snapshot is aws rds create-db-snapshot with required flags.

2. Step 2: Match parameters

   Use --db-instance-identifier for the instance and --db-snapshot-identifier for the snapshot name.

3. Final Answer:

   aws rds create-db-snapshot --db-instance-identifier mydbinstance --db-snapshot-identifier mydbsnapshot -> Option A

4. Quick Check:

   Correct CLI command = aws rds create-db-snapshot --db-instance-identifier mydbinstance --db-snapshot-identifier mydbsnapshot [OK]

Hint: Use create-db-snapshot with instance and snapshot IDs [OK]

Common Mistakes:

• Using incorrect command verbs like backup-db-instance
• Mixing parameter names like --snapshot-name instead of --db-snapshot-identifier
• Assuming snapshot creation is automatic without command

3. Given this AWS CLI output snippet after running aws rds describe-db-snapshots --db-instance-identifier mydbinstance:

{
  "DBSnapshots": [
    {"DBSnapshotIdentifier": "snapshot1", "Status": "available"},
    {"DBSnapshotIdentifier": "snapshot2", "Status": "creating"}
  ]
}

What does the status "creating" mean for snapshot2?

medium

A. "snapshot2" is currently being created and not ready for restore.

B. "snapshot2" is ready and can be used to restore the database.

C. "snapshot2" creation failed and needs retry.

D. "snapshot2" is deleted but still listed temporarily.

Solution

1. Step 1: Understand snapshot status meanings

   Status "creating" means the snapshot process is in progress and not yet complete.

2. Step 2: Interpret the impact on usage

   While "creating", the snapshot cannot be used for restore until status changes to "available".

3. Final Answer:

   "snapshot2" is currently being created and not ready for restore. -> Option A

4. Quick Check:

   Status creating = snapshot in progress [OK]

Hint: Creating means snapshot not ready yet [OK]

Common Mistakes:

• Assuming creating means snapshot is ready
• Confusing creating with failed or deleted status
• Thinking snapshot is deleted but still listed

4. You wrote this AWS CLI command to create a manual snapshot but got an error:

aws rds create-db-snapshot --db-instance-identifier mydbinstance

What is missing that causes the error?

medium

A. The --region parameter is required for all commands.

B. The --db-instance-identifier value is incorrect and must be the snapshot name.

C. The --db-snapshot-identifier parameter with a snapshot name is missing.

D. The command must be run with sudo privileges.

Solution

1. Step 1: Check required parameters for create-db-snapshot

   The command requires both --db-instance-identifier and --db-snapshot-identifier to name the snapshot.

2. Step 2: Identify missing parameter

   The command lacks --db-snapshot-identifier, so AWS cannot create the snapshot without a name.

3. Final Answer:

   The --db-snapshot-identifier parameter with a snapshot name is missing. -> Option C

4. Quick Check:

   Missing snapshot ID causes error [OK]

Hint: Always provide snapshot name with --db-snapshot-identifier [OK]

Common Mistakes:

• Forgetting to specify snapshot identifier
• Assuming region is always mandatory
• Thinking sudo is needed for AWS CLI commands

5. You want to keep daily backups of your RDS instance for 7 days automatically and also keep a manual snapshot before a major update that you want to keep indefinitely. Which combination of settings and actions achieves this?

hard

A. Create a manual snapshot daily and delete old ones after 7 days; no automated backups.

B. Disable automated backups and create 7 manual snapshots daily plus one before update.

C. Enable automated backups with 7-day retention and rely only on them for the update.

D. Enable automated backups with 7-day retention and create a manual snapshot before update.

Solution

1. Step 1: Set automated backups retention

   Enable automated backups with a 7-day retention period to keep daily backups automatically.

2. Step 2: Create manual snapshot before update

   Manually create a snapshot before the update to keep a permanent backup unaffected by retention.

3. Final Answer:

   Enable automated backups with 7-day retention and create a manual snapshot before update. -> Option D

4. Quick Check:

   Automated + manual snapshot = daily + permanent backup [OK]

Hint: Automated backups expire; manual snapshots keep forever [OK]

Common Mistakes:

• Disabling automated backups losing daily backups
• Relying only on automated backups for permanent backup
• Manually creating many snapshots instead of using automated backups