DP-300 Practice Question: Monitor, configure, and optimize database resources
Which TWO metrics from sys.dm_db_resource_stats should you monitor to identify a disk IO bottleneck in an Azure SQL Database?
⚠ Common exam trap
DP-300 often tests whether candidates can map a symptom (disk IO bottleneck) to the correct DMV columns — the trap is picking avg_cpu_percent or avg_memory_usage_percent because they are the most familiar resource metrics.
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
✓
avg_data_io_percent
The two correct metrics are C, avg_data_io_percent, and E, avg_log_write_percent. avg_data_io_percent reports the percentage of the data-file IOPS/throughput limit consumed by the database, so sustained values near 100% directly indicate a data-file disk IO bottleneck. avg_log_write_percent reports the percentage of the log-write throughput limit consumed, so elevated values reveal a transaction-log write bottleneck. Together these two IO-related counters isolate disk IO pressure in Azure SQL Database. The unmarked options do not belong: avg_cpu_percent (A) measures compute utilization, max_size_percent (B) tracks storage-space consumption against the size limit, and avg_memory_usage_percent (D) measures memory pressure, none of which identify disk IO bottlenecks.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
avg_cpu_percent
Why it's wrong here
avg_cpu_percent measures processor utilisation, so it identifies compute pressure rather than the I/O subsystem. It is tempting because sustained CPU saturation often accompanies slow queries, and would be the correct metric when diagnosing a CPU bottleneck or deciding whether to scale vCores.
- ✗
max_size_percent
Why it's wrong here
max_size_percent reports the largest database size reached relative to the size limit, tracking storage capacity rather than throughput or latency. It is tempting because it does flag a resource ceiling, and would be the correct metric when monitoring whether a database is approaching its maximum allotted size before scaling.
- ✓
avg_data_io_percent
Why this is correct
avg_data_io_percent reports the percentage of the data-file IOPS limit consumed, directly exposing data disk saturation. Monitoring it identifies a disk IO bottleneck caused by read or write activity against data files, satisfying the stem's requirement in Azure SQL Database.
- ✗
avg_memory_usage_percent
Why it's wrong here
avg_memory_usage_percent reports buffer pool consumption against the memory limit, indicating memory pressure rather than disk throughput. It is tempting because memory pressure causes paging and apparent slowness, and would be the correct metric when determining whether to increase memory-optimised resources or investigate cache eviction.
- ✓
avg_log_write_percent
Why this is correct
avg_log_write_percent reports the percentage of the log-write IOPS limit consumed, directly exposing transaction-log disk saturation. Monitoring it identifies a disk IO bottleneck caused by write-heavy log activity, satisfying the stem's requirement to detect IO constraints in Azure SQL Database.
Go deeper
Related to this question
Learn chapter
Securing Data at Rest and in Transit
Key term
Azure SQL Performance Tuning
Azure SQL Performance Tuning is the process of optimizing the speed and efficiency of queries and database operations in Microsoft Azure SQL Database or SQL Managed Instance to reduce latency and improve throughput.
About these practice questions
Courseiva writes every DP-300 question from scratch — 574 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Microsoft exam blueprint
This DP-300 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 DP-300 exam.