You have created several block volumes in the us-phoenix-1 region in a specific compart-ment. The compartment can be identified by the following…

The question requires a Monitoring Query Language (MQL) query to show the maximum read IOPS for all block volumes in a specific compartment at a one-minute interval. The correct metric is IopsRead. The interval is specified as [1m]. Filtering by compartment is done with {compartmentId = '...'}. To aggregate all results from the compartment into a single line showing the maximum value, the grouping() function (with no dimensions specified) is used, followed by the .max() aggregator. This combination correctly fulfills all requirements.

A. This query uses the mean() aggregator, which calculates the average, not the maximum as required by the question.
B. This query is missing the grouping() function. While some simple queries might work without it, the standard MQL syntax for aggregating multiple time series into one is to use grouping().
C. This query uses the IopsWrite metric, which tracks write operations, not the required read operations. It also incorrectly uses the mean() aggregator.

1. Oracle Cloud Infrastructure Documentation, "Monitoring Query Language (MQL) Reference", Section: Query Structure. (This section details the components of an MQL query: Metric[interval]{dimensionkey="dimensionvalue"}.grouping().statistic()).

2. Oracle Cloud Infrastructure Documentation, "Block Volume Metrics", Section: ociblockstorage Metrics. (This page lists IopsRead as the metric for "Read operations per second").