How to manage memory allocations for a Niagara 4 Web Supervisor

Proper memory allocation is crucial for Niagara 4 Web Supervisor performance. This guide covers how to configure, monitor, and optimise memory settings to ensure reliable operation and prevent out-of-memory errors.

Overview

Memory management for Niagara 4 Web Supervisor involves:

• Java Heap Memory: Primary memory for Java Virtual Machine (JVM)
• Native Memory: Memory for native libraries and system resources
• Garbage Collection: Automatic memory management and cleanup
• Memory Monitoring: Tracking memory usage and performance

Understanding Memory Architecture

Memory Components

Niagara Web Supervisor uses:

• Heap Memory: Where Java objects are stored
• Non-Heap Memory: Metaspace, code cache, native memory
• System Memory: Operating system memory usage
• Reserved Memory: Memory reserved but not yet used

Memory Limits

Default memory allocations:

• Initial Heap: Typically 256MB or 512MB
• Maximum Heap: Typically 1GB or 2GB
• Metaspace: Grows as needed (Java 8+)
• Native Memory: Varies based on system resources

Step-by-Step Configuration

Step 1: Locate Supervisor Configuration

1. Identify Supervisor Installation: Locate Niagara Web Supervisor installation directory
2. Configuration Files: Find supervisor configuration files:
   • supervisor.conf or supervisor.ini
   • wrapper.conf (if using Java Service Wrapper)
   • niagara.env or environment configuration files

Common locations:

• C:\Niagara\ (Windows)
• /opt/niagara/ (Linux)
• Installation-specific directories

Step 2: Access Configuration Files

1. Stop Supervisor: Stop the Niagara Web Supervisor service before editing
2. Backup Configuration: Create backup of configuration files
3. Open Configuration: Open configuration file in text editor with administrator privileges

Step 3: Configure Initial Heap Size

Set the initial Java heap size:

For wrapper.conf (Java Service Wrapper):

wrapper.java.initmemory=512

For supervisor.conf:

java.initmemory=512

For command-line or environment:

-Xms512m

Where 512 is the initial heap size in megabytes.

Step 4: Configure Maximum Heap Size

Set the maximum Java heap size:

For wrapper.conf:

wrapper.java.maxmemory=2048

For supervisor.conf:

java.maxmemory=2048

For command-line:

-Xmx2048m

Where 2048 is the maximum heap size in megabytes.

Step 5: Configure Garbage Collection

Configure garbage collection settings for optimal performance:

For wrapper.conf or command-line:

wrapper.java.additional.1=-XX:+UseG1GC
wrapper.java.additional.2=-XX:MaxGCPauseMillis=200
wrapper.java.additional.3=-XX:G1HeapRegionSize=16m

Or for older Java versions:

wrapper.java.additional.1=-XX:+UseParallelGC
wrapper.java.additional.2=-XX:ParallelGCThreads=4

Step 6: Configure Metaspace (Java 8+)

For Java 8 and later, configure Metaspace:

wrapper.java.additional.4=-XX:MetaspaceSize=256m
wrapper.java.additional.5=-XX:MaxMetaspaceSize=512m

Step 7: Configure Native Memory

Set native memory limits if needed:

wrapper.java.additional.6=-XX:MaxDirectMemorySize=512m

Step 8: Save and Restart

1. Save Configuration: Save all configuration file changes
2. Restart Supervisor: Restart the Niagara Web Supervisor service
3. Verify Startup: Check supervisor starts successfully
4. Monitor Memory: Monitor memory usage after restart

Memory Configuration Examples

Small Installation (< 1000 points)

wrapper.java.initmemory=256
wrapper.java.maxmemory=1024
wrapper.java.additional.1=-XX:+UseG1GC
wrapper.java.additional.2=-XX:MaxGCPauseMillis=200

Medium Installation (1000-5000 points)

wrapper.java.initmemory=512
wrapper.java.maxmemory=2048
wrapper.java.additional.1=-XX:+UseG1GC
wrapper.java.additional.2=-XX:MaxGCPauseMillis=200
wrapper.java.additional.3=-XX:G1HeapRegionSize=16m

Large Installation (> 5000 points)

wrapper.java.initmemory=1024
wrapper.java.maxmemory=4096
wrapper.java.additional.1=-XX:+UseG1GC
wrapper.java.additional.2=-XX:MaxGCPauseMillis=200
wrapper.java.additional.3=-XX:G1HeapRegionSize=32m
wrapper.java.additional.4=-XX:MetaspaceSize=512m
wrapper.java.additional.5=-XX:MaxMetaspaceSize=1024m

Monitoring Memory Usage

Using Workbench

1. Connect to Supervisor: Connect Workbench to Supervisor
2. System Monitor: Navigate to System Monitor or Performance Monitor
3. Memory Metrics: View memory usage metrics:
   • Heap memory used/available
   • Non-heap memory usage
   • Garbage collection statistics
   • Memory pool details

Using Platform Services

1. Platform Services: Access Platform Services in Workbench
2. JVM Monitor: Use JVM monitoring tools
3. Memory Statistics: Review memory statistics and trends

Using Operating System Tools

Windows:

tasklist /FI "IMAGENAME eq java.exe" /FO TABLE

Or use Task Manager to monitor Java process memory.

Linux:

ps aux | grep java
top -p <java_pid>

Or use jstat for detailed JVM statistics:

jstat -gc <pid> 1000

Troubleshooting

Out of Memory Errors

If experiencing out-of-memory errors:

1. Increase Maximum Heap: Increase -Xmx value
2. Check System Memory: Ensure system has sufficient RAM
3. Review Memory Usage: Identify memory-intensive operations
4. Optimise Code: Review and optimise custom code
5. Garbage Collection: Tune garbage collection settings

High Memory Usage

If memory usage is consistently high:

1. Monitor Trends: Track memory usage over time
2. Identify Leaks: Look for memory leaks in applications
3. Review Configuration: Check for unnecessary services
4. Optimise Applications: Optimise custom applications
5. Increase Allocation: Consider increasing maximum heap if needed

Garbage Collection Issues

If experiencing GC problems:

1. GC Logging: Enable GC logging to analyse patterns
2. GC Tuning: Adjust GC algorithm and parameters
3. Heap Size: Ensure heap size is appropriate
4. GC Frequency: Monitor GC frequency and duration
5. Professional Tuning: Consider professional JVM tuning

Performance Degradation

If performance degrades:

1. Memory Pressure: Check for memory pressure
2. GC Overhead: Monitor garbage collection overhead
3. Heap Fragmentation: Check for heap fragmentation
4. Native Memory: Monitor native memory usage
5. System Resources: Check overall system resources

Best Practices

Memory Sizing

• Start Conservative: Begin with conservative memory settings
• Monitor and Adjust: Monitor usage and adjust as needed
• Leave Headroom: Don't allocate all available memory
• System Resources: Reserve memory for operating system

Garbage Collection

• Choose Appropriate GC: Select GC algorithm for your workload
• Monitor GC Performance: Regularly monitor GC statistics
• Tune Gradually: Make incremental GC tuning changes
• Test Changes: Test GC changes in development first

Monitoring

• Regular Monitoring: Monitor memory usage regularly
• Set Alerts: Configure alerts for high memory usage
• Trend Analysis: Analyse memory usage trends
• Documentation: Document memory configuration and changes

Maintenance

• Regular Reviews: Periodically review memory configuration
• Update Settings: Update settings as system grows
• Optimise Applications: Optimise applications to reduce memory usage
• Keep Current: Stay current with Niagara and Java updates

Advanced Configuration

Custom JVM Arguments

Add custom JVM arguments for specific needs:

wrapper.java.additional.7=-XX:+HeapDumpOnOutOfMemoryError
wrapper.java.additional.8=-XX:HeapDumpPath=/var/log/niagara/
wrapper.java.additional.9=-XX:+PrintGCDetails
wrapper.java.additional.10=-Xlog:gc*:file=/var/log/niagara/gc.log

Memory Profiling

Enable memory profiling for analysis:

1. Enable Profiling: Configure JVM for profiling
2. Use Profiling Tools: Use tools like VisualVM, JProfiler
3. Analyse Results: Analyse profiling results
4. Optimise Based on Results: Make optimisations based on analysis

Related Topics

• How to calculate the quantity of Global Capacity Points consumed in a Station
• What to do when a Platform login is failing

Additional Resources

• Niagara 4 System Administration Guide
• Java Virtual Machine Tuning Guide
• Garbage Collection Tuning Documentation
• Memory Management Best Practices