IBM i Performance Monitoring

Monitor system performance including collection services configuration, temporary storage usage, disk I/O metrics, and memory pool performance using SQL services from QSYS2.

Available Tools

The ibmi CLI is the primary tool for executing performance queries. Set SKILL_DIR to this skill's installed location (the directory containing this SKILL.md file):

# SKILL_DIR = directory containing this SKILL.md
# Examples: ./skills/performance, ~/.claude/skills/performance

# List all performance tools
ibmi tools --tools "$SKILL_DIR/tools/" --toolset performance_default

# Run a specific tool
ibmi tool get_collection_services_config --tools "$SKILL_DIR/tools/"

# Ad-hoc SQL for custom queries
ibmi sql "SELECT * FROM QSYS2.COLLECTION_SERVICES_INFO"

The ibmi-mcp-server also provides execute_sql and describe_sql_object for MCP-connected agents.

Service Selection Guide

Collection Services

• QSYS2.COLLECTION_SERVICES_INFO -- Configuration, intervals, retention, categories

Temporary Storage

• QSYS2.SYSTMPSTG -- Temporary storage per bucket and per job

Disk I/O

• QSYS2.SYSDISKSTAT -- Elapsed I/O statistics per disk unit

Memory Performance

• QSYS2.MEMORY_POOL() -- Page faults, thread transitions, tuning settings

Key Capabilities

Collection Services Management

• Configuration -- Active collection, library, profile, intervals
• Categories -- What data categories are collected and at what interval
• Retention -- How long performance data is kept
• Monitoring -- Whether system monitoring is enabled

Temporary Storage Analysis

• Named Buckets -- System-level named temporary storage areas with current/peak sizes
• Unnamed Storage -- Aggregate usage of unnamed temporary storage
• Per-job Usage -- Which jobs consume the most temporary storage
• Limit Tracking -- Job-level storage limits vs current usage

Disk I/O Performance

• Per-unit Metrics -- Read/write requests, data transferred, busy percentage
• Elapsed Statistics -- I/O during the measurement interval
• Hot Spots -- Identify the busiest disk units

Memory Pool Performance

• Fault Rates -- Database and non-database page faults per pool
• Thread Transitions -- Active-to-wait, wait-to-ineligible counts
• Tuning Parameters -- Priority, min/max size, fault thresholds

Common Use Cases

1. Collection services audit -- Verify performance data is being collected
2. Temp storage investigation -- Find jobs using excessive temporary storage
3. Named bucket monitoring -- Track system temp storage bucket growth
4. Disk I/O hot spots -- Identify the busiest disk units
5. Memory pressure detection -- Find pools with high page fault rates
6. Performance baseline -- Capture metrics for trend analysis
7. Capacity planning -- Analyze storage and I/O trends

Quick Examples

Check collection services configuration

ibmi tool get_collection_services_config --tools "$SKILL_DIR/tools/"

View collection categories

ibmi tool get_collection_categories --tools "$SKILL_DIR/tools/"

Top temp storage consumers by job

ibmi tool get_temp_storage_by_job --tools "$SKILL_DIR/tools/"

Disk I/O performance

SELECT UNIT_NUMBER, ASP_NUMBER,
       ELAPSED_READ_REQUESTS, ELAPSED_WRITE_REQUESTS,
       ELAPSED_PERCENT_BUSY
  FROM QSYS2.SYSDISKSTAT
  WHERE ELAPSED_IO_REQUESTS > 0
  ORDER BY ELAPSED_PERCENT_BUSY DESC
  FETCH FIRST 10 ROWS ONLY;

Named temp storage buckets

SELECT GLOBAL_BUCKET_NAME, BUCKET_CURRENT_SIZE, BUCKET_PEAK_SIZE
  FROM QSYS2.SYSTMPSTG
  WHERE GLOBAL_BUCKET_NAME IS NOT NULL
  ORDER BY BUCKET_CURRENT_SIZE DESC;

Pre-built Tools

The tools/performance.yaml file provides 7 ready-to-use tools:

Tool	Description
get_collection_services_config	Collection services configuration and settings
get_collection_categories	Collection categories with their intervals
get_temp_storage_buckets	Named temporary storage bucket usage
get_unnamed_temp_storage	Aggregate unnamed temporary storage usage
get_temp_storage_by_job	Temporary storage consumption by job
get_disk_io_performance	Disk I/O performance stats per unit
get_memory_pool_performance	Memory pool fault rates and tuning metrics

ibmi tool <tool_name> --tools "$SKILL_DIR/tools/"          # Execute
ibmi tool <tool_name> --tools "$SKILL_DIR/tools/" --dry-run # Preview SQL
ibmi tools show <tool_name> --tools "$SKILL_DIR/tools/"     # View details

Reference Documentation

• Performance Services Catalog -- Available SQL services
• Example SQL Patterns -- Working query examples
• IBM COLLECTION_SERVICES_INFO -- View documentation
• IBM SYSTMPSTG -- View documentation