SC-100 Design security solutions for infrastructure Practice Question
You are designing a backup strategy for Azure virtual machines that host a mission-critical application. The solution must support daily backups with a retention of 30 days for daily backups, weekly backups retained for 12 weeks, and monthly backups retained for 3 years. What should you use?
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
✓
Azure Backup with a backup policy that specifies daily, weekly, and monthly retention.
Azure Backup with a backup policy that specifies daily, weekly, and monthly retention (option D) is correct because Azure Backup for virtual machines natively supports long-term retention through policy rules that define daily, weekly, monthly, and yearly retention durations, exactly matching the required 30-day daily, 12-week weekly, and 3-year monthly schedule. Azure Backup also provides application-consistent snapshots and recovery points for mission-critical VMs without custom scripting. Option A is wrong because Azure Files backup targets file shares, not VM disks, and requires custom scripting that Azure Backup handles natively. Option B is wrong because Azure Disk Backup only supports snapshot-based retention up to a limited period and does not provide the multi-tier daily/weekly/monthly retention policy required. Option C is wrong because Azure Site Recovery is a disaster-recovery replication service, not a backup solution with retention policies.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Azure Files backup with a custom script.
Why it's wrong here
Azure Files backup protects file share data, not the VM's underlying OS and data disks, so it cannot restore the virtual machine itself. A custom script merely copies or snapshots disk files without Azure Backup's managed recovery points, coordinated application-consistent VSS snapshots, or policy-based retention. This approach leaves you with unverified, fragmented backups and no integrated restore experience for a full VM. Therefore, it is not a suitable backup strategy for Azure VMs.
- ✗
Azure Disk Backup with a snapshot schedule.
Why it's wrong here
Azure Disk Backup creates incremental snapshot recovery points for managed disks, but its operational tier retention is limited to a daily granularity, typically only 30 days, and does not support weekly or monthly retention tiers. A snapshot schedule alone cannot satisfy the requirement to keep backups for weeks or months. Azure Backup's VM backup solution, by contrast, uses a Recovery Services vault and a backup policy that accommodates multi-tier retention. Thus, Disk Backup is incorrect when the design calls for daily, weekly, and monthly retention.
- ✗
Azure Site Recovery with a recovery plan.
Why it's wrong here
Azure Site Recovery continuously replicates Azure VMs to a secondary region for disaster recovery, with recovery point objectives of 30 seconds or more, and its recovery plans simply sequence failover across multiple VMs. It is a replication and failover service, not a backup service that creates independent, long-term retention points. The replicated copies are not designed to be retained for daily, weekly, or monthly compliance periods, and recovery plans do not perform backup operations. Therefore, relying on Site Recovery with a recovery plan fails to meet the stated backup retention requirements.
- ✓
Azure Backup with a backup policy that specifies daily, weekly, and monthly retention.
Why this is correct
Azure Backup with a VM backup policy precisely matches the requirement: the policy allows a daily, weekly, and monthly retention schedule, with each retention tier preserving recovery points for up to 180 days, 10 years, and 10 years respectively. You can also adjust retention to meet compliance needs, and Azure Backup stores recovery points in the Recovery Services vault. This gives you application-consistent, crash-consistent, or file-consistent snapshots and supports instant restore from snapshots. It is the correct strategy for multi-tier retention of Azure VMs.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SC-100 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SC-100 exam.