Emergency procedures

This guide covers emergency procedures for recovering your VoIPmonitor system from critical failures, including runaway processes, high CPU usage, and system unresponsiveness.

Emergency: "Too High Load" Error in Live Sniffer

When the Live Sniffer or sniffer service crashes with a "too high load" error message, this is an intentional **protection feature**, not a crash. The monitor proactively shuts down to maintain data integrity when system load is too high to process packets reliably.

Understanding the "Too High Load" Message

The "too high load" termination is a **safety feature** designed to:

• Prevent corrupted packet capture under excessive system load
• Maintain data integrity by stopping before data loss occurs
• Protect against system unstability

This is NOT a crash or bug - it is the expected behavior when the system cannot keep up with traffic load.

Step 1: Assess True CPU Load with htop

Overall "system CPU usage" can be misleading because it averages across all cores. To understand actual load:

Use htop to view per-thread and per-core CPU usage

htop

• In htop, view CPU load for individual threads/cores, not just the average
• Load is displayed per CPU core (each bar represents one core)
• A single core running at 100% can appear as 25% overall on a 4-core system

Step 2: Compare Load Average Against Core Count

Understanding load average (LA) is critical:

• Load average represents the average number of processes waiting for CPU time
• Compare the load average against your total number of CPU cores
• Generally, a load average lower than the core count is acceptable

For example:

• 8-core system: Load average of 4.0 (50% capacity) is acceptable
• 4-core system: Load average of 8.0 (200% capacity) is overloaded
• 16-core system: Load average of 12.0 (75% capacity) is acceptable

Display load average:

# View current load average
uptime

# Or use top/htop (shown in summary line)
# Format: load average: 1 min, 5 min, 15 min

Step 3: Identify the Bottleneck

If load average exceeds core count consistently:

• Check if a single process is pegging one core at 100% (htop will show this clearly)
• Verify if the issue affects multiple cores (system-wide overload)
• Review performance logs for thread-specific CPU usage

For system-wide overload solutions, see Scaling and Performance Tuning.

Emergency: VoIPmonitor Process Consuming Excessive CPU or System Unresponsive

When a VoIPmonitor process consumes excessive CPU (e.g., ~3000% or more) or causes the entire system to become unresponsive, follow these immediate steps:

Immediate Action: Force-Terminate Runaway Process

If the system is still minimally responsive via SSH or requires out-of-band management (iDRAC, IPMI, console):

1. Identify the Process ID (PID)

# Using htop (if available)
htop

# Or using ps
ps aux | grep voipmonitor

Look for the voipmonitor process consuming the most CPU resources. Note down the PID (process ID number).

2. Forcefully terminate the process

kill -9 <PID>

Replace <PID> with the actual process ID number identified in step 1.

3. Verify system recovery

# Check CPU usage has returned to normal
top

# Check if the process was terminated
ps aux | grep voipmonitor

The system should become responsive again immediately after the process is killed. CPU utilization should drop significantly.

Optional: Stop and Restart the Service (for persistent issues)

If the problem persists or the service needs to be cleanly restarted:

# Stop the voipmonitor service
systemctl stop voipmonitor

# Verify no zombie processes remaining
killall voipmonitor

# Restart the service
systemctl start voipmonitor

# Verify service status
systemctl status voipmonitor

Caution: When using systemd service management, avoid using the deprecated service command as it can cause systemd to lose track of the daemon. Always use systemctl commands or direct process commands like killall.

Root Cause Analysis: Why Did the CPU Spike?

After recovering the system, investigate the root cause to prevent recurrence. Common causes include:

SIP REGISTER Flood / Spaming Attack

Massive volumes of SIP REGISTER messages from malicious IPs can overwhelm the VoIPmonitor process.

• Detection: Check recent alert triggers in the VoIPmonitor GUI > Alerts > Sent Alerts for SIP REGISTER flood alerts
• Immediate mitigation: Block attacker IPs at the network edge (SBC, firewall, iptables)
• Long-term prevention: Configure anti-fraud rules with custom scripts to auto-block, see SIP REGISTER Flood Mitigation

Packet Capture Overload (pcapcommand)

The pcapcommand feature forks a program for every call, which can generate up to 500,000 interrupts per second.

• Detection: Check /etc/voipmonitor.conf for a pcapcommand line
• Immediate fix: Comment out or remove the pcapcommand directive and restart the service
• Alternative: Use the built-in cleaning spool functionality (maxpoolsize, cleanspool) instead

Excessive RTP Processing Threads

High concurrent call volumes can overload RTP processing threads.

• Detection: Check performance logs for high tRTP_CPU values (sum of all RTP threads)
• Mitigation:

callslimit = 2000  # Limit max concurrent calls

Audio Feature Overhead

Silence detection and audio conversion are CPU-intensive operations.

• Detection: Check if silencedetect or saveaudio are enabled
• Mitigation:

  silencedetect = no
  # saveaudio = wav  # Comment out if not needed
  

See Scaling and Performance Tuning for detailed performance optimization strategies.

Preventive Measures

Once the root cause is identified, implement these preventive configurations:

Monitor CPU Trends

Use collectd or your existing monitoring system to track CPU usage over time and receive alerts before critical thresholds are reached.

Anti-Fraud Auto-Blocking

Configure Anti-Fraud rules with custom scripts to automatically block attacker IPs when a flood is detected. See the Anti-Fraud documentation for PHP script examples using iptables or ipset.

Network Edge Protection

Block SIP REGISTER spam and floods at your network edge (SBC, firewall) before traffic reaches VoIPmonitor. This provides better performance and reduces CPU load on the monitoring system.

Emergency: GUI and CLI Frequently Inaccessible Due to Memory Exhaustion

When the VoIPmonitor GUI and CLI become frequently inaccessible or the server becomes unresponsive due to Out of Memory (OOM) conditions, follow these steps to identify and resolve the issue.

Diagnose OOM Events

The Linux kernel out-of-memory (OOM) killer terminates processes when RAM is exhausted.

Check the kernel ring buffer for OOM events

dmesg -T | grep -i killed

If you see messages like "Out of memory: Kill process" or "invoke-oom-killer", your system is running out of physical RAM.

Immediate Relief: Reduce Memory Allocation

Reduce memory consumption by tuning both MySQL and VoIPmonitor parameters.

1. Reduce MySQL Buffer Pool Size

Edit the MySQL configuration file (typically /etc/my.cnf.d/mysql-server.cnf or /etc/mysql/my.cnf for Debian/Ubuntu):

[mysqld]
# Reduce from 8GB to 6GB (adjust based on available RAM)
innodb_buffer_pool_size = 6G

A good starting point is innodb_buffer_pool_size = RAM * 0.5 - max_buffer_mem * 0.8. For example, on a 16GB server with 8GB allocated to max_buffer_mem, set innodb_buffer_pool_size to approximately 6GB.

2. Reduce VoIPmonitor Buffer Memory

Edit /etc/voipmonitor.conf and decrease the max_buffer_mem value:

[general]
# Reduce from 8000 to 6000 (adjust based on available RAM)
max_buffer_mem = 6000

The max_buffer_mem parameter limits the maximum RAM allocation for the packet buffer. Typical values range from 2000-8000 MB depending on traffic volume and call rates.

3. Restart the affected services

systemctl restart mysqld
systemctl restart voipmonitor

Monitor the system to confirm stability.

Long-term Solution: Increase RAM

For sustained production operation, increase the server's physical RAM:

• Minimum: Add at least 16 GB of additional RAM to eliminate OOM conditions
• Performance benefit: After the RAM upgrade, you can safely increase innodb_buffer_pool_size to improve MySQL performance
• Recommended settings: Set innodb_buffer_pool_size to 50-70% of total RAM and max_buffer_mem based on your traffic requirements

See Sniffer Configuration for details on VoIPmonitor memory settings.

Emergency: Diagnosing System Hangs and Collecting Core Dump Evidence

When the VoIPmonitor system hangs, packet buffer (heap) spikes to 100%, and a single CPU core is pegged at 100%, you need to diagnose the issue and collect evidence for developer analysis before restarting.

1. 1. 1. Identify the Problematic Thread

Use the Manager API to identify which sniffer thread is consuming excessive CPU resources.

# Query thread statistics from the sensor
echo 'sniffer_threads' | nc <sensor_ip> 5029

Replace <sensor_ip> with the actual IP address of your VoIPmonitor sensor. Look for a thread showing approximately 100% CPU usage. This indicates the specific processing thread that is causing the hang.

1. 1. 1. Generate Core Dump for Developer Analysis

If a thread is pegged at 100% and the system needs to be analyzed by VoIPmonitor developers, generate a core dump before restarting:

1. Find the VoIPmonitor process ID (PID)

ps aux | grep voipmonitor | grep -v grep

2. Attach to the process with gdb and generate a core dump

gdb -p <PID_of_voipmonitor>
# Within gdb, generate the core dump
gcore <output_file>

# Example:
gdb -p 12345
(gdb) gcore /tmp/voipmonitor_hang.core

The core dump file provides developers with a complete snapshot of the process state at the moment of the hang, including memory, registers, and stack traces.

3. Detach from gdb and quit

 detach
quit

1. 1. 1. Restore Service and Collect Evidence

After collecting the diagnostic evidence, restart the service to restore operation:

systemctl restart voipmonitor

Provide the following files to VoIPmonitor support for analysis:

• Core dump file (from gcore command)
• Thread statistics output (from sniffer_threads command)
• Performance logs (/var/log/syslog showing the hang period)
• Configuration file (/etc/voipmonitor.conf)

Important: Core dump files can be very large (several GB depending on max_buffer_mem). Ensure you have sufficient disk space and consider compressing the file before transferring it to support.

Emergency: System Freezes on Every Update Attempt

If the VoIPmonitor sensor becomes unresponsive or hangs each time you attempt to update it through the Web GUI:

1. SSH into the sensor host

2. Execute the following commands to forcefully stop and restart

killall voipmonitor
systemctl stop voipmonitor
systemctl start voipmonitor

This sequence ensures zombie processes are terminated, systemd is fully stopped, and a clean service restart occurs. Verify the sensor status in the GUI to confirm it is responding correctly.

Emergency: Binary Not Found After Crash

If the VoIPmonitor service fails to start after a crash with error "Binary not found" for /usr/local/sbin/voipmonitor:

1. Check for a renamed binary

ls -l /usr/local/sbin/voipmonitor_*

The crash recovery process may have renamed the binary with an underscore suffix.

2. If found, rename it back

mv /usr/local/sbin/voipmonitor_ /usr/local/sbin/voipmonitor

3. Restart the service

systemctl start voipmonitor
systemctl status voipmonitor

Verify the service starts correctly.

Out-of-Band Management Scenarios

When the system is completely unresponsive and cannot be accessed via SSH:

• Use your server's out-of-band management system:

 * Dell iDRAC
 * HP iLO
 * Supermicro IPMI
 * Other vendor-specific BMC/management tools

• Actions available via OBM:

 * Access virtual console (KVM-over-IP)
 * Send NMI (Non-Maskable Interrupt) for system dump
 * Force power cycle
 * Monitor hardware health

See Sniffer Troubleshooting for more diagnostic procedures.

Emergency: Service Restart Loop with "packetbuffer: MEMORY IS FULL" and "Cannot bind to port"

If the VoIPmonitor service enters a restart loop, logging packetbuffer: MEMORY IS FULL and displaying Cannot bind to port [5029] errors, the issue can have multiple root causes. The "MEMORY IS FULL" error message is ambiguous and can indicate either RAM exhaustion or disk I/O bottleneck.

Critical: Distinguish Between RAM and Disk I/O Issues

The symptoms appear identical, but the root causes and solutions are different:

RAM-Based Memory Issue	Disk I/O Performance Issue	Network Throughput Bottleneck
Memory buffer fills due to excessive concurrent calls or traffic floods	Memory buffer fills because disk cannot write fast enough to drain it	Probe fills packet buffer while sending packets to central server (insufficient network bandwidth)
Solution: Increase max_buffer_mem, enable packetbuffer_compress, or limit concurrent calls	Solution: Upgrade storage, move spool to faster disk, or resolve I/O bottleneck	Solution: Switch to Local Processing mode (packetbuffer_sender=no) or use packetbuffer_compress=yes to reduce network traffic. See Step 6 below.

Step 0: Check Kernel Messages for Storage Errors (Critical First Step!)

Before investigating performance issues, check the kernel message buffer for storage hardware or filesystem errors. This is the first diagnostic step to distinguish between hardware/failure problems and performance bottlenecks.

1. Check kernel messages for storage errors

# Check the kernel message buffer for storage-related errors
dmesg -T | grep -i -E "i/o error|disk|storage|filesystem|ext4|xfs|nfs|scsi"

• What to look for:

 * I/O errors (e.g., "Buffer I/O error", "critical medium error")
 * Filesystem errors (e.g., "EXT4-fs error", "XFS error")
 * NFS-specific errors (e.g., "NFS: server not responding", "NFS: device not ready")
 * SCSI/SATA errors (e.g., "Task abort", "Device failed")
 * ATA SMART errors indicating disk degradation

2. If kernel errors are present

• • This indicates a hardware or filesystem issue, not a performance bottleneck
  • Solutions depend on the specific error:

 * Replace failing disk hardware
 * Repair filesystem (fsck)
 * Resolve NFS connectivity issues (network, server availability)
 * Check RAID controller for failures
 * Fix underlying kernel/storage configuration issues

3. If kernel messages are clean (no errors)

• • Proceed to Step 1 below to investigate disk I/O performance bottlenecks

For more detailed kernel event investigation, use:

# View all recent kernel messages with timestamps
dmesg -T | tail -100

# Filter for time range (example: last 1 hour)
journalctl -k --since "1 hour ago"

Step 1: Check for Disk I/O Bottleneck (Performance Issue)

If dmesg -T shows no storage errors (Step 0), the issue is likely a performance bottleneck in the storage subsystem. Check for disk I/O problems on the spool directory (typically /var/spool/voipmonitor).

1. Monitor disk utilization with iostat

# Monitor disk I/O in real-time (1-second intervals)
iostat -x 1

• What to look for: A value near 100% in the %util column indicates the disk is operating at maximum capacity
• Symptoms:** High %util, high await (average wait time), or high queue depth

2. Perform a write speed test to the spool directory

# Test sequential write speed (adjust count based on available disk space)
# Note: dd test uses O_DIRECT to bypass cache for accurate measurement
dd if=/dev/zero of=/var/spool/voipmonitor/testfile bs=1M count=1024 oflag=direct conv=fdatasync

# Clean up test file
rm /var/spool/voipmonitor/testfile

• Interpretation: A very slow write speed (e.g., less than 50 MB/s on HDDs or significantly lower than expected SSD speed) confirms a storage bottleneck
• For SSD/NVMe, expect 400+ MB/s sequential writes
• For HDDs, expect 80-150 MB/s sequential writes (7200 RPM)

3. Check for I/O wait (Linux monitoring)

# Check if the system is spending significant time waiting for I/O
# High 'wa' (wait) percentage indicates disk bottleneck
top
# or
vmstat 1

• Look for high %wa (I/O wait) in the CPU section

Step 2: Resolve Disk I/O Bottleneck

If disk I/O tests confirm the issue:

• Option 1: Upgrade storage hardware

 ** Move /var/spool/voipmonitor to a faster local SSD or NVMe drive
 ** Consider RAID 10 for better performance and redundancy
 ** If using NFS, move spool to local storage instead of network-mounted filesystem

• Option 2: Tune storage configuration

 ** Check if the disk is operating in degraded mode (RAID rebuild in progress)
 ** Verify the storage controller firmware is up to date
 ** Disable unnecessary monitoring or indexing (e.g., updatedb, antivirus scanning) on the spool directory

• Option 2a: NFS Network Storage Performance

 If /var/spool/voipmonitor is mounted on NFS:
 ** Check network latency to NFS server:

     # Ping test to NFS server
     ping -c 10 <nfs_server_ip>

     # Measure NFS-specific latency/mount stats
     # Requires nfsiostat from nfs-utils package
     nfsiostat 1

 ** Check NFS server response time and network congestion
 ** Consider upgrading network (e.g., 10GbE) for higher NFS throughput
 ** Use TCP mount options for reliability (e.g., mount -t nfs -o tcp)
 ** Verify NFS server has sufficient disk I/O performance
 ** If NFS is the bottleneck, move spool directory to local SSD storage

• Option 3: Move spool directory to faster volume

  # Stop service
  systemctl stop voipmonitor

  # Mount faster disk to /var/spool/voipmonitor
  # Or create symlink:
  mv /var/spool/voipmonitor /var/spool/voipmonitor.backup
  ln -s /path/to/fast/disk/voipmonitor /var/spool/voipmonitor

  # Restart service
  systemctl start voipmonitor

For detailed disk performance benchmarking, see I/O Performance Measurement for advanced testing with fio and ioping.

Step 3: Check for RAM-Based Memory Issue

If disk I/O is healthy but the error persists, the issue is RAM-based memory exhaustion.

1. Check RAM allocation

# Check current memory usage
free -h

2. Increase memory buffer limits

Edit /etc/voipmonitor.conf:

Recommended Values for "MEMORY IS FULL" Errors
ringbuffer	For very high traffic (>200Mbps) or severe packet loss scenarios, increase to 2000 MB (maximum allowed). Default is 50 MB, recommended for >100Mbit traffic is 500 MB.
max_buffer_mem	For high concurrent call loads (5000+ calls) or persistent buffer issues, increase to 8000 MB. Default is 2000 MB, typical tuning is 4000 MB for moderate loads.
packetbuffer_compress	Enable if RAM is constrained (increases CPU usage to reduce memory footprint).

[general]
# HIGH TRAFFIC CONFIGURATION - Prevent "MEMORY IS FULL" errors
# Max ringbuffer for very high traffic traffic/serious packet loss
ringbuffer = 2000

# Increase buffer memory for high concurrent call loads
max_buffer_mem = 8000

# Enable compression to save RAM at CPU cost
packetbuffer_compress = yes

# Optional: Limit concurrent calls to prevent overload
callslimit = 2000

Alternative: Moderate Traffic Configuration

[general]
# For moderate traffic (100-200 Mbit, 2000-5000 concurrent calls)
ringbuffer = 500
max_buffer_mem = 4000
packetbuffer_compress = yes

3. Restart and monitor

systemctl restart voipmonitor
journalctl -u voipmonitor -f

IMPORTANT: This guidance applies to RAM-based memory issues where the local server cannot process traffic fast enough. For distributed deployments where probes send packets to a central server, see Step 6 below - the solution is typically to switch to Local Processing mode, not to increase max_buffer_mem.

See Sniffer Configuration for more memory tuning options.

Step 4: Alternative Root Cause - Adaptive Jitterbuffer Overload

If the "packetbuffer: MEMORY IS FULL" and "HEAP FULL" errors occur even after adjusting max_buffer_mem, the issue may be caused by the adaptive jitterbuffer feature consuming excessive memory during processing. The adaptive jitterbuffer (which simulates jitter up to 500ms) is CPU and memory-intensive and can trigger heap exhaustion on high-traffic systems.

1. Check if jitterbuffer_adapt is enabled

# Check voipmonitor.conf for jitter buffer settings
grep jitterbuffer /etc/voipmonitor.conf

If jitterbuffer_adapt = yes is set, this features may be causing the memory exhaustion.

2. Disable adaptive jitterbuffer

Edit /etc/voipmonitor.conf and set:

[general]
# Disable adaptive jitterbuffer to prevent memory/CPU exhaustion
jitterbuffer_adapt = no

3. Restart the service

systemctl restart voipmonitor

4. Verify the error is resolved

# Monitor for MEMORY IS FULL errors
journalctl -u voipmonitor -f

Important Trade-offs:

• Disabling jitterbuffer_adapt removes the CPU/memory overhead but also disables MOS_adaptive score calculation
• Fixed jitterbuffer modes (jitterbuffer_f1 for 50ms, jitterbuffer_f2 for 200ms) remain available and consume significantly less resources
• If MOS quality scoring is required, consider using jitterbuffer_f2 = yes instead

This solution is particularly effective when the system crashes with both "MEMORY IS FULL" and "HEAP FULL" errors simultaneously, indicating the adaptive jitterbuffer heap is overflowing during real-time packet processing.

Step 5: Clear Stale Port 5029 Bindings

The "Cannot bind to port [5029]" error occurs when a zombie process still holds the Manager API port. This prevents clean restarts.

# Force kill all VoIPmonitor processes
killall -9 voipmonitor

# Ensure service is stopped
systemctl stop voipmonitor

# Verify no processes are running
ps aux | grep voipmonitor

# Restart service
systemctl start voipmonitor

After clearing zombie processes and addressing the root cause (I/O or RAM), the service should start successfully without the bind error.

Step 6: Network Throughput Bottleneck in Distributed Deployments

In distributed client-server mode (remote probes sending data to a central server), a different type of "MEMORY IS FULL" error can occur when the **network throughput between probes and central server** becomes the bottleneck, particularly during peak traffic hours.

Distributed Mode: Network Bottleneck Scenario
Symptoms:	* "packetbuffer: MEMORY IS FULL" errors on remote probes * Missing CDRs and significant delays in CDR display, especially during peak traffic * VoIP Monitor server shows extremely high memory utilization (99%) * Problems occur during peak hours when network traffic is highest
Root Cause:	Using Packet Mirroring mode (packetbuffer_sender=yes) on probes with insufficient network bandwidth to the central server. The probe's packetbuffer fills because it cannot send raw packets fast enough over the network.
Solution:	Switch to Local Processing mode (packetbuffer_sender=no) if probe hardware has sufficient CPU and disk resources.

Identify Network Bottleneck vs Local Resource Issues

To confirm the bottleneck is network-related rather than local resource constraints:

1. Check probe configuration

# On remote probe - check current packetbuffer_sender setting
grep packetbuffer_sender /etc/voipmonitor.conf

If packetbuffer_sender = yes, the probe may be sending raw packets to central server, requiring high network bandwidth.

2. Verify probe local resources are healthy

# Check if probe has sufficient free RAM
free -h

# Check if probe disk I/O is not a bottleneck
iostat -x 1

# Check CPU load
top

If the probe has sufficient free RAM, healthy disk I/O, and reasonable CPU load, the bottleneck is likely network throughput.

3. Check network throughput during peak hours

Measure the actual network utilization between probe and central server during peak traffic:

# Monitor network interface throughput (e.g., eth0)
sar -n DEV 1

# or use iftop for real-time per-connection monitoring (if available)
iftop -i eth0

If network utilization approaches or saturates the link capacity during peak traffic, the network is the bottleneck.

Solution: Switch to Local Processing Mode

If probes have sufficient CPU and disk resources, switching from Packet Mirroring to Local Processing mode eliminates network throughput issues.

Impact of Switching to Local Processing Mode
Before (packetbuffer_sender=yes): Probe sends raw packets over network to central server. Bandwidth requirement equals VoIP traffic volume. After (packetbuffer_sender=no): Probe analyzes packets locally and sends only CDRs. Network traffic is minimal.
Pros:	* Drastically reduces network load between probes and central server * Eliminates MEMORY IS FULL errors caused by network bottlenecks * CDRs appear promptly (no network delay) * Scales better with multiple probes
Cons / Trade-offs:	* Increases CPU and RAM usage on probes (they perform full analysis) * PCAP files are stored on probes, not central server * Delay when downloading PCAPs for replay (file must be transferred from remote probe on demand) * Requires sufficient probe resources (CPU, disk, RAM)

Configuration change on remote probes

Edit /etc/voipmonitor.conf on each affected probe:

[general]
# Switch from Packet Mirroring to Local Processing
packetbuffer_sender = no

# Ensure probe has MySQL credentials to write CDRs directly to database
# Or configure central server's server_bind to accept CDRs from probes

Restart the probe service

systemctl restart voipmonitor

Prerequisites for Local Processing Mode

Before switching to packetbuffer_sender=no, ensure probes meet these requirements:

Requirement	Why It Matters
Sufficient CPU	Probes perform full SIP/RTP analysis, which is CPU-intensive
Sufficient RAM	Probes need max_buffer_mem and ringbuffer resources for their traffic volume
Fast local disk	PCAP files are stored on probes. Disk I/O performance affects capture reliability
Database connectivity	Probes write CDRs directly to MySQL/MariaDB (via configured database credentials) or send to central server via client-server protocol

If probes lack sufficient CPU or disk resources, Local Processing mode may not be viable. In this case, consider:

• Upgrading probe hardware
• Improving network bandwidth (e.g., 10GbE)
• Reducing traffic volume per probe (add more probes)

Tuning max_buffer_mem for Network Throughput Bottlenecks

If you must continue using Packet Mirroring mode (packetbuffer_sender=yes) temporarily before switching to Local Processing, you can tune max_buffer_mem differently than for RAM-based memory issues:

max_buffer_mem Guidance by Bottleneck Type
RAM-Based Memory Issue (Step 3)	Local server cannot process traffic fast enough. Solution: INCREASE max_buffer_mem (e.g., 4000-8000 MB) to give more headroom
Network Bottleneck (distributed mode)	Probe cannot send packets to central server fast enough. Solution: DECREASE max_buffer_mem (e.g., from 8000 to 2000 MB) so the buffer fails faster without exhausting RAM, enabling quicker recovery from network congestion.

Edit /etc/voipmonitor.conf on the probe:

[general]
# REDUCE max_buffer_mem for network throughput bottlenecks
# This causes the buffer to fail sooner (releasing memory) instead of
# continuing to occupy RAM waiting for a network connection that cannot keep up
max_buffer_mem = 2000

# Enable compression to reduce network traffic
packetbuffer_compress = yes

Restart the probe service:

systemctl restart voipmonitor

For detailed documentation on distributed architecture configuration, see Distributed Architecture: Client-Server Mode.

Related Issues

For performance tuning and scaling guidance, see:

• Scaling and Performance Tuning Guide
• I/O Performance Measurement
• High-Performance Setup

Related Documentation

• Scaling and Performance Tuning Guide - For performance optimization
• Anti-Fraud Rules - For attack detection and mitigation
• Sniffer Troubleshooting - For systematic diagnostic procedures
• High-Performance Setup - For optimizing high-traffic deployments
• Systemd Service Management - For service management best practices

AI Summary for RAG

Summary: This article provides emergency procedures for recovering VoIPmonitor from critical failures. It covers the "too high load" error in Live Sniffer (an intentional protection feature, not a crash, designed to maintain data integrity by shutting down when system load is too high), steps to assess true CPU load using htop (view per-thread and per-core CPU usage, not just averages), how to compare load average (LA) against total CPU cores (load average lower than core count is generally acceptable), how to view load average with uptime or top/htop, and identifying bottlenecks when load exceeds core count. It also covers steps to force-terminate runaway processes consuming excessive CPU (including kill -9 and systemctl commands), root cause analysis for CPU spikes (SIP REGISTER floods, pcapcommand, RTP threads, audio features), OOM memory exhaustion troubleshooting (checking dmesg for killed processes, reducing innodb_buffer_pool_size and max_buffer_mem), preventive measures (monitoring, anti-fraud auto-blocking, network edge protection), recovery procedures for system freezes during updates and binary issues after crashes, out-of-band management scenarios, and CRITICAL troubleshooting for service restart loop with "packetbuffer: MEMORY IS FULL" and "Cannot bind to port [5029]" errors. The MEMORY IS FULL error has multiple root causes: (1) Kernel storage errors (Step 0: check dmesg -T for I/O errors, filesystem errors, NFS errors, SCSI/SATA errors, SMART errors before investigating performance) or (2) Disk I/O performance bottleneck (Step 1: check iostat -x 1 for 100% utilization, test write speed with dd to /var/spool/voipmonitor with oflag=direct; Step 2: resolve by upgrading storage, moving spool, or for NFS check network latency with ping and nfsiostat) or (3) RAM-based memory exhaustion (Step 3: increase max_buffer_mem, enable packetbuffer_compress, ringbuffer, callslimit) or (4) Adaptive jitterbuffer overload (Step 4: check jitterbuffer settings with grep jitterbuffer /etc/voipmonitor.conf, disable jitterbuffer_adapt=no if enabled, which also disables MOS_adaptive scoring but keeps jitterbuffer_f1/f2 available) or (5) Network throughput bottleneck in distributed deployments (Step 6: occurs when using Packet Mirroring mode packetbuffer_sender=yes on remote probes with insufficient network bandwidth to central server, causing packetbuffer to fill during peak traffic. Symptoms include MEMORY IS FULL errors, missing CDRs, and significant CDR display delays, especially during peak hours. Solution: Switch probes to Local Processing mode packetbuffer_sender=no if they have sufficient CPU and disk resources. This eliminates network bottleneck by having probes analyze packets locally and send only CDRs. Trade-offs include increased probe CPU/RAM usage, PCAPs stored on probes (delay for replay/download), and requires sufficient probe resources. Prerequisites: sufficient probe CPU for full SIP/RTP analysis, sufficient RAM for max_buffer_mem and ringbuffer, fast local disk for PCAP storage, database connectivity. If probes lack resources, consider upgrading probe hardware, improving network bandwidth (10GbE), or adding more probes to reduce traffic per probe). Check probe configuration with grep packetbuffer_sender, verify probe local resources (free -h, iostat -x 1, top), monitor network utilization with sar -n DEV or iftop). The "Cannot bind to port [5029]" error (Step 5) requires clearing zombie processes (killall -9 voipmonitor, systemctl stop voipmonitor). For NFS storage, use ping and nfsiostat to diagnose network latency.

Keywords: emergency recovery, high CPU, system unresponsive, runaway process, kill process, kill -9, systemctl, SIP REGISTER flood, pcapcommand, performance optimization, out-of-band management, iDRAC, iLO, IPMI, crash recovery, OOM, out of memory, memory exhaustion, dmesg -T, dmesg, kernel messages, storage errors, I/O errors, filesystem errors, ext4 errors, xfs errors, NFS errors, SCSI errors, SATA errors, SMART errors, innodb_buffer_pool_size, max_buffer_mem, MEMORY IS FULL, HEAP FULL, packetbuffer, disk I/O, I/O bottleneck, iostat -x 1, iostat, disk utilization, %util, write speed test, dd oflag=direct, spool directory, SSD, NVMe, RAID, Cannot bind to port 5029, zombie process, Manager API port, port 5029, restart loop, storage performance, I/O wait, %wa, jitterbuffer, jitterbuffer_adapt, adaptive jitterbuffer, jitterbuffer_f1, jitterbuffer_f2, MOS_adaptive, CPU intensive, memory exhaustion, NFS, NFS latency, ping, nfsiostat, network storage, 10GbE, packetbuffer_compress, ringbuffer, callslimit, fsck, too high load, sniffer crash, Live Sniffer, htop, load average, LA, CPU cores, per-thread CPU monitoring, per-core CPU usage, data integrity, protection feature, distributed mode, client-server mode, remote probes, central server, network throughput, network bottleneck, packetbuffer_sender, packetbuffer_sender=yes, packetbuffer_sender=no, Local Processing, Packet Mirroring, peak traffic, missing CDRs, CDR delay, display delay, network utilization, sar -n DEV, iftop, probe resources, central server bottleneck

Key Questions:

• What does "too high load" error mean in Live Sniffer?
• Is "too high load" crash a bug or a feature?
• Why does the sniffer terminate with "too high load" error?
• How to assess true CPU load in VoIPmonitor?
• How to use htop to monitor per-thread and per-core CPU usage?
• Why is overall system CPU usage misleading?
• How to interpret load average (LA) against CPU cores?
• What is a good load average value for my system?
• How to check load average with uptime or top/htop?
• How to identify CPU bottlenecks when load exceeds core count?
• What to do when VoIPmonitor consumes 3000% CPU or system becomes unresponsive?
• How to forcefully terminate a runaway VoIPmonitor process?
• What are common causes of CPU spikes in VoIPmonitor?
• How to mitigate SIP REGISTER flood attacks causing high CPU?
• How to diagnose OOM (Out of Memory) events?
• How to fix GUI and CLI frequently inaccessible due to memory exhaustion?
• How to reduce memory usage of MySQL and VoIPmonitor?
• What is max_buffer_mem and how to configure it?
• How to restart VoIPmonitor service after a crash?
• What to do if service binary is not found after crash?
• How to prevent VoIPmonitor from freezing during GUI updates?
• What tools can help diagnose VoIPmonitor performance issues?
• What causes "packetbuffer: MEMORY IS FULL" error message?
• How to distinguish between RAM exhaustion and disk I/O bottleneck?
• What is the first diagnostic step for "MEMORY IS FULL" errors?
• How to use dmesg -T to check for storage errors?
• What type of errors to look for in dmesg when MEMORY IS FULL occurs?
• How to check for I/O errors, filesystem errors, NFS errors in kernel messages?
• What to if kernel dmesg shows storage errors vs no errors?
• How to check for disk I/O performance issues causing restart loops?
• How to use iostat to diagnose disk utilization?
• How to perform write speed test to /var/spool/voipmonitor directory?
• What does "Cannot bind to port [5029]" error mean?
• How to clear zombie processes holding port 5029?
• How to resolve disk I/O bottleneck for VoIPmonitor?
• How to move spool directory to faster storage?
• What is the correct dd command to test disk write speed?
• What causes "HEAP FULL" errors in VoIPmonitor?
• How is jitterbuffer_adapt related to MEMORY IS FULL errors?
• What is the solution for MEMORY IS FULL + HEAP FULL crashes caused by jitterbuffer_adapt?
• Why should I disable jitterbuffer_adapt?
• What happens when I set jitterbuffer_adapt = no?
• What is the trade-off when disabling jitterbuffer_adapt?
• Can I still use jitterbuffer_f1 and jitterbuffer_f2 with jitterbuffer_adapt disabled?
• How to check NFS network latency causing MEMORY IS FULL?
• What tools to use for NFS diagnostics (ping, nfsiostat)?
• How to improve NFS storage performance for VoIPmonitor?
• Can MEMORY IS FULL errors be caused by network throughput bottlenecks in distributed mode?
• What causes MEMORY IS FULL errors on remote probes in client-server mode?
• How to identify if MEMORY IS FULL is caused by network bottleneck in distributed deployment?
• How does packetbuffer_sender mode affect network traffic between probes and central server?
• What is the difference between Local Processing and Packet Mirroring in distributed mode?
• How to switch from Packet Mirroring to Local Processing mode on remote probes?
• What is the solution for MEMORY IS FULL caused by insufficient network bandwidth between probes and central server?
• What are the trade-offs when switching to Local Processing mode (packetbuffer_sender=no)?
• What are the prerequisites for using Local Processing mode on remote probes?
• How to check if network throughput is the bottleneck in distributed VoIPmonitor deployment?
• How to monitor network utilization between remote probes and central server (sar -n DEV, iftop)?
• How to verify probe resources (CPU, RAM, disk) are sufficient for Local Processing mode?
• What configuration change fixes MEMORY IS FULL errors caused by bandwidth limitations in distributed mode?
• What happens when probes use packetbuffer_sender=yes with insufficient network bandwidth?
• Why do CDRs have significant delays during peak traffic in distributed mode?
• How to fix missing CDRs and MEMORY IS FULL errors on remote probes?