Linux SSH Plugin – Add Support for “Logical Maximum Size” and Percentage Thresholds in Files-Size Mode

Persona:

Centreon administrator

Problem to solve:

In the current Linux SSH – Files-Size mode, thresholds are calculated based only on the raw directory size in bytes. For directories subject to operational "soft limits" or logical growth policies (where no system-level quotas are enabled), the lack of a reference capacity makes percentage-based monitoring impossible. This requires administrators to manually recalculate byte-based thresholds whenever a logical limit is adjusted.

Current behavior:

The plugin retrieves the directory size using the du command via SSH but does not provide a parameter to define a reference capacity. Thresholds are strictly compared against absolute byte counts, and no percentage usage is calculated in the status output or performance data.

Expected outcome:

Allow the plugin to use a user-defined "Logical Maximum Size" as an optional reference for threshold calculation. Users could choose between:

• Default: Thresholds based on the raw directory size in bytes.

• Optional: Thresholds based on a percentage of a manually defined --max-size.

Potential solutions:

• Add a new option (e.g., --max-size) to define the 100% reference value (supporting units like G, M, or bytes).

• Add a new option (e.g., --use-percentage) to interpret warning and critical inputs as percentage values of the maximum size.

• Enhance performance data by populating the "max" field of the size metric and adding a dedicated size_prct metric.

• Update the status output to display the usage ratio (e.g., "Used / Max (Usage %)").

Benefits / Impact:

• Scalability: Enables the use of generic Service Templates where only a capacity macro is adjusted per host.

• Operational Clarity: Provides intuitive feedback (percentage of a limit) rather than raw byte counts for operators.