CPU and Memory Monitoring

Understanding CPU and Memory Metrics

Server Scout continuously monitors your server's CPU and memory performance, providing essential insights into system health and resource utilisation. These core metrics help you identify performance bottlenecks, plan capacity, and maintain optimal server performance.

CPU Monitoring

Server Scout tracks CPU usage as a percentage across all available cores, giving you a comprehensive view of processor utilisation. The system calculates CPU percentage by measuring the time spent on active processes versus idle time across all CPU cores.

Key CPU metrics collected:

• Overall CPU usage percentage (0-100%)
• Individual core utilisation
• System load averages (1, 5, and 15-minute intervals)
• Process count and resource consumption

Memory Monitoring

Memory monitoring encompasses several critical metrics that provide a complete picture of your server's memory landscape:

Memory metrics tracked:

• Total Memory: Physical RAM installed on the system
• Used Memory: Currently allocated memory (including buffers and cache)
• Available Memory: Memory available for new applications
• Memory Usage Percentage: Used memory as a percentage of total
• Swap Usage: Virtual memory utilisation when physical RAM is exhausted

Data Collection Frequency

Server Scout employs a two-tiered approach to data collection, balancing real-time visibility with efficient storage:

1. Real-time Collection: Metrics are gathered every 5 seconds, providing immediate insight into current system performance
2. Historical Aggregation: Data is aggregated into longer intervals for historical analysis and trending

This approach ensures you can monitor immediate performance whilst maintaining comprehensive historical records for capacity planning and trend analysis.

Reading Real-time Graphs

The server detail page presents CPU and memory data through intuitive real-time graphs. Here's how to interpret them effectively:

CPU Graph Interpretation

The CPU graph displays usage as a percentage over time. Look for:

• Sustained peaks: Consistently high CPU usage may indicate resource constraints
• Spikes: Brief peaks are normal, but frequent spikes might suggest inefficient processes
• Baseline patterns: Understanding normal usage patterns helps identify anomalies

Memory Graph Analysis

Memory graphs show both absolute values and percentages:

• Available memory trend: Declining available memory over time may indicate memory leaks
• Swap activity: Any significant swap usage often signals insufficient RAM
• Usage patterns: Normal applications show predictable memory consumption patterns

Normal vs Concerning Levels

CPU Usage Guidelines

Normal levels:

• Web servers: 10-40% average usage
• Database servers: 20-60% depending on workload
• Application servers: 15-50% typical range

Concerning indicators:

• Sustained usage above 80% for extended periods
• Constant 100% utilisation
• Unusual spikes without corresponding application activity

Memory Usage Thresholds

Healthy memory usage:

• 60-80% utilisation is generally acceptable
• Consistent available memory reserves
• Minimal or no swap usage

Warning signs:

• Memory usage consistently above 85%
• Available memory below 10% of total
• Active swap usage exceeding 10% of physical RAM
• Steadily increasing memory consumption without explanation

Setting Up Alerts

Configure proactive monitoring by establishing CPU and memory alerts through Server Scout's notification system:

CPU Alert Configuration

1. Navigate to your server's alert settings
2. Set CPU threshold alerts:

- Warning level: 70-80% for 5+ minutes - Critical level: 90%+ for 2+ minutes

1. Configure notification preferences (email, SMS, webhook)

Memory Alert Setup

Establish memory thresholds based on your server's role:

1. Available Memory Alerts:

- Warning: Less than 15% available memory - Critical: Less than 5% available memory

1. Memory Usage Percentage:

- Warning: Above 85% utilisation - Critical: Above 95% utilisation

1. Swap Usage Alerts:

- Warning: Swap usage above 25% - Critical: Swap usage above 50%

Best Practices

• Review historical trends weekly to identify gradual performance degradation
• Correlate CPU and memory spikes with application deployments or traffic changes
• Adjust alert thresholds based on your server's normal operating patterns
• Monitor both metrics together, as high memory usage often leads to increased CPU utilisation due to swapping

Regular monitoring of these fundamental metrics ensures your servers maintain optimal performance and helps prevent issues before they impact your applications or users.