---
id: 45905849-b554-4c81-94c2-281f0616ae76
---

# Excessive memory usage by Tomcat.
---

This incident type refers to the situation where the Tomcat server is utilizing more memory than it should, causing system instability and performance issues. This can happen due to a variety of factors such as memory leaks, improper configuration, or application code issues. It is important to address this incident promptly to prevent system failures and ensure optimal application performance.

### Parameters
```shell
export PID="PLACEHOLDER"

export OLD_MEMORY_LIMIT="PLACEHOLDER"

export NEW_MEMORY_LIMIT="PLACEHOLDER"

export TOMCAT_CONFIG_DIR="PLACEHOLDER"

export NEW_THREAD_COUNT="PLACEHOLDER"

export TOMCAT_USER="PLACEHOLDER"

export TOMCAT_GROUP="PLACEHOLDER"
```

## Debug

### Check the current memory usage
```shell
free -m
```

### Check the processes running on the system
```shell
ps aux
```

### Find the PID of Tomcat
```shell
ps aux | grep tomcat
```

### Check the memory usage of Tomcat
```shell
pmap -x ${PID}
```

### Check the Java version that Tomcat is running on
```shell
ps -ef | grep tomcat | grep -v grep | awk '{print $11}' | xargs -r readlink -f | xargs -r dirname | xargs -r dirname | xargs -r readlink -f | xargs -r -I {} {}/bin/java -version
```

### Check the Tomcat configuration
```shell
cat /etc/tomcat/server.xml
```

### Check the Tomcat log files for errors or warnings
```shell
tail -n 100 /var/log/tomcat/catalina.out
```

### Check the heap usage of Tomcat
```shell
jstat -gcutil ${PID} 1000
```

### Check the thread usage of Tomcat
```shell
jstack -l ${PID} | grep -Ei 'daemon|java.lang.Thread.State'
```

### Check for any memory leaks
```shell
jmap -histo:live ${PID} | head -n 20
```

### Check the JVM arguments that are being used by Tomcat
```shell
ps -ef | grep tomcat | grep -v grep | awk '{print $11}' | xargs -r readlink -f | xargs -r dirname | xargs -r dirname | xargs -r readlink -f | xargs -r -I {} {}/bin/java -XX:+PrintFlagsFinal -version | grep -Ei 'heapsize|stacksize|metaspacesize|direct|verbose'
```

## Repair

### Increase the memory allocation for the Tomcat server.
```shell


#!/bin/bash



# Stop Tomcat

sudo systemctl stop tomcat



# Update the memory allocation in the Tomcat configuration file

sudo sed -i 's/-Xmx${OLD_MEMORY_LIMIT}/-Xmx${NEW_MEMORY_LIMIT}/g' /path/to/tomcat/conf/catalina.sh



# Start Tomcat

sudo systemctl start tomcat





chmod +x increase_tomcat_memory.sh


```

### Reduce the number of threads used by Tomcat.
```shell


#!/bin/bash



# Stop the Tomcat service

sudo service tomcat stop



# Navigate to the Tomcat configuration directory

cd ${TOMCAT_CONFIG_DIR}



# Backup the original configuration file

sudo cp server.xml server.xml.bak



# Edit the server.xml file to reduce the number of threads

sudo sed -i 's/Connector port="8080"/Connector port="8080" maxThreads="${NEW_THREAD_COUNT}"/' server.xml



# Save and close the configuration file

sudo chmod 644 server.xml

sudo chown ${TOMCAT_USER}:${TOMCAT_GROUP} server.xml



# Restart the Tomcat service

sudo service tomcat start


```

This incident type refers to the situation where the Tomcat server is utilizing more memory than it should, causing system instability and performance issues. This can happen due to a variety of factors such as memory leaks, improper configuration, or application code issues. It is important to address this incident promptly to prevent system failures and ensure optimal application performance.


When too many requests are sent to a Tomcat server, the thread pools that handle these requests can run out of available threads. This means that incoming requests will not be processed, leading to service degradation or even a complete outage. This incident type is critical for web applications that rely on Tomcat as their application server.


Tomcat thread pool exhaustion.

Tomcat Server Crash incident type refers to a situation where the Tomcat Server, an open-source web server and servlet container, becomes unresponsive and stops functioning. This can result in a complete or partial system outage, leading to a disruption in the delivery of web applications and services. The root cause of the crash can be attributed to a variety of factors such as misconfiguration, network or hardware issues, software bugs, or excessive server load. It is critical to address this incident quickly to minimize the impact on users and restore normal system functionality.


Tomcat Server Crash

This incident type occurs when the PermGen or Metaspace usage of the Tomcat server exceeds 90%. PermGen and Metaspace are memory pools used for storing class definitions and metadata of the Java virtual machine (JVM). When these memory pools reach their maximum capacity, the server may experience performance issues or even crash. This incident requires immediate attention from the software engineer to investigate the root cause and take appropriate actions to resolve the issue.


Tomcat PermGen or Metaspace Usage exceeds 90%

This incident type is related to the Tomcat server, which is a popular open-source Java application server. It occurs when the available threads in the connection pool are running low, which means that there are not enough resources to serve incoming requests. This can cause delays or even failures in the application's performance, impacting the end-user experience. It is important to monitor and address this issue promptly to ensure that the application runs smoothly and efficiently.


Tomcat Low Available Threads in Connection Pool

In software engineering, a large number of suspended threads in Tomcat is an incident type that occurs when a high number of threads are created but are blocked from executing. This can happen due to a variety of reasons, such as slow database queries, network latency, or resource contention. When this occurs, the system may become unresponsive or slow, causing a degradation in performance or even a complete system failure. It is important to investigate and resolve this issue as quickly as possible to ensure the system can continue to function properly.


Tomcat Large Number of Suspended Threads Incident.

```shell
export PID="PLACEHOLDER"

export OLD_MEMORY_LIMIT="PLACEHOLDER"

export NEW_MEMORY_LIMIT="PLACEHOLDER"

export TOMCAT_CONFIG_DIR="PLACEHOLDER"

export NEW_THREAD_COUNT="PLACEHOLDER"

export TOMCAT_USER="PLACEHOLDER"

export TOMCAT_GROUP="PLACEHOLDER"
```


### Check the current memory usage

```shell
free -m
```

### Check the processes running on the system

```shell
ps aux
```

### Find the PID of Tomcat

```shell
ps aux | grep tomcat
```

### Check the memory usage of Tomcat

```shell
pmap -x ${PID}
```

### Check the Java version that Tomcat is running on

```shell
ps -ef | grep tomcat | grep -v grep | awk '{print $11}' | xargs -r readlink -f | xargs -r dirname | xargs -r dirname | xargs -r readlink -f | xargs -r -I {} {}/bin/java -version
```

### Check the Tomcat configuration

```shell
cat /etc/tomcat/server.xml
```

### Check the Tomcat log files for errors or warnings

```shell
tail -n 100 /var/log/tomcat/catalina.out
```

### Check the heap usage of Tomcat

```shell
jstat -gcutil ${PID} 1000
```

### Check the thread usage of Tomcat

```shell
jstack -l ${PID} | grep -Ei 'daemon|java.lang.Thread.State'
```

### Check for any memory leaks

```shell
jmap -histo:live ${PID} | head -n 20
```

### Check the JVM arguments that are being used by Tomcat

```shell
ps -ef | grep tomcat | grep -v grep | awk '{print $11}' | xargs -r readlink -f | xargs -r dirname | xargs -r dirname | xargs -r readlink -f | xargs -r -I {} {}/bin/java -XX:+PrintFlagsFinal -version | grep -Ei 'heapsize|stacksize|metaspacesize|direct|verbose'
```


### Increase the memory allocation for the Tomcat server.

```shell


#!/bin/bash



# Stop Tomcat

sudo systemctl stop tomcat



# Update the memory allocation in the Tomcat configuration file

sudo sed -i 's/-Xmx${OLD_MEMORY_LIMIT}/-Xmx${NEW_MEMORY_LIMIT}/g' /path/to/tomcat/conf/catalina.sh



# Start Tomcat

sudo systemctl start tomcat





chmod +x increase_tomcat_memory.sh


```

### Reduce the number of threads used by Tomcat.

```shell


#!/bin/bash



# Stop the Tomcat service

sudo service tomcat stop



# Navigate to the Tomcat configuration directory

cd ${TOMCAT_CONFIG_DIR}



# Backup the original configuration file

sudo cp server.xml server.xml.bak



# Edit the server.xml file to reduce the number of threads

sudo sed -i 's/Connector port="8080"/Connector port="8080" maxThreads="${NEW_THREAD_COUNT}"/' server.xml



# Save and close the configuration file

sudo chmod 644 server.xml

sudo chown ${TOMCAT_USER}:${TOMCAT_GROUP} server.xml



# Restart the Tomcat service

sudo service tomcat start


```


Excessive memory usage by Tomcat.

Overview

Parameters

Debug

Check the current memory usage

Check the processes running on the system

Find the PID of Tomcat

Check the memory usage of Tomcat

Check the Java version that Tomcat is running on

Check the Tomcat configuration

Check the Tomcat log files for errors or warnings

Check the heap usage of Tomcat

Check the thread usage of Tomcat

Check for any memory leaks

Check the JVM arguments that are being used by Tomcat

Repair

Increase the memory allocation for the Tomcat server.

Reduce the number of threads used by Tomcat.

Learn more

Related Runbooks

Tomcat thread pool exhaustion.

Tomcat Server Crash

Tomcat PermGen or Metaspace Usage exceeds 90%

Tomcat Low Available Threads in Connection Pool

Support