DBS-C01 Management and Operations Practice Question

A database administrator is troubleshooting a backup failure for an Amazon RDS for SQL Server DB instance. The error message states 'Insufficient storage capacity for backup. Free storage space is 0 GB.' The DB instance has 200 GB allocated storage. What is the most likely cause?

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

✓

The DB instance has insufficient free storage space to perform the backup.

RDS requires free storage space to perform backups and manage transaction logs. With 0 GB free, the backup fails. Option B is incorrect because the number of manual snapshots does not affect the storage capacity of the DB instance; manual snapshots are stored separately in Amazon S3. Option C is incorrect because although transaction logs consume allocated storage, the error specifically indicates insufficient free storage for the backup operation, and the most likely cause is that the instance lacks free storage. Option D is incorrect because setting the backup retention period to 0 days disables automated backups entirely; it does not cause a backup failure due to insufficient storage.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✓
The DB instance has insufficient free storage space to perform the backup.
Why this is correct
The DB instance has insufficient free storage space to perform the backup. This is correct because RDS uses allocated storage for backup operations. When free space is 0 GB, backups cannot proceed.
✗
The DB instance has reached the maximum number of manual snapshots.
Why it's wrong here
The DB instance has reached the maximum number of manual snapshots. This is incorrect because manual snapshots are stored in Amazon S3, not in the allocated storage, and do not consume the instance's free space. The error is about storage capacity, not snapshot count.
✗
The transaction logs are consuming all allocated storage.
Why it's wrong here
The transaction logs are consuming all allocated storage. This is incorrect as the primary cause; while transaction logs can fill storage, the immediate cause of the backup failure is the lack of free space. The error indicates free storage is 0 GB, which could be due to logs, data, or other factors. The most direct cause is insufficient free space.
✗
The backup retention period is set to 0 days, disabling automated backups.
Why it's wrong here
The backup retention period is set to 0 days, disabling automated backups. This is incorrect because even if backup retention is 0, automated backups are disabled, but that would not cause a storage capacity error; it would simply not perform backups. The error message indicates a storage issue, not a configuration issue.

Quick reference

AWS S3 Storage Class Comparison

Storage Class	Min Duration	Retrieval	Use Case
S3 Standard	None	Immediate	Frequently accessed data
S3 Standard-IA	30 days	Immediate	Infrequent access, rapid retrieval
S3 One Zone-IA	30 days	Immediate	Non-critical infrequent data
S3 Intelligent-Tiering	None	Immediate–hours	Unknown or changing access patterns
S3 Glacier Instant	90 days	Milliseconds	Archive with instant retrieval
S3 Glacier Flexible	90 days	Minutes–hours	Archive, flexible retrieval
S3 Glacier Deep Archive	180 days	Hours	Long-term compliance archive

Go deeper

DBS-C01 Management and Operations Practice Question

Why each option matters

Option-by-option breakdown

AWS S3 Storage Class Comparison

Related to this question