sar

Overview

The sar (System Activity Reporter) command collects, reports, and saves system activity information. It provides historical and real-time system statistics.

Syntax

sar [options] [interval [count]]

Common Options

Option Description
-A All statistics
-b IO transfer rates
-B Paging statistics
-c Process creation
-d Block device activity
-n Network statistics
-P Per-processor stats
-q Queue length
-r Memory utilization
-S Swap space stats
-u CPU utilization
-v Kernel tables
-w Task creation
-W Swapping stats

Output Types

Type Description
CPU Processor usage
Memory Memory stats
Swap Swap activity
IO Input/output
Network Network stats
Process Process stats
Queue System queue
Disk Disk activity

Key Use Cases

  1. System monitoring
  2. Performance analysis
  3. Capacity planning
  4. Trend analysis
  5. Troubleshooting

Examples with Explanations

Example 1: CPU Usage

sar -u

CPU statistics

Example 2: Memory

sar -r

Memory statistics

Example 3: Network

sar -n DEV

Network interface stats

Common Usage Patterns

  1. Real-time monitoring:

    sar 1 5

  2. Daily stats:

    sar -f /var/log/sa/sa01

  3. All stats:

    sar -A

Additional Resources

Best Practices

  1. Regular collection
  2. Data retention
  3. Baseline creation
  4. Trend analysis
  5. Alert setup

Performance Analysis

  1. System load
  2. Resource usage
  3. Bottlenecks
  4. Capacity issues
  5. Performance trends

Troubleshooting

  1. System issues
  2. Resource constraints
  3. Performance problems
  4. Capacity limits
  5. Trend analysis

Data Collection

  1. Historical data
  2. Real-time stats
  3. System logs
  4. Performance metrics
  5. Resource usage