Tuning Performance

This section describes some recommended performance tuning configurations to optimize the App Manager. It assumes that you have set up the App Manager on Unix/Linux, which are recommended for a production deployment. A distributed setup is also recommended for most production systems. Out of all components of an App Manager distributed setup, the API Gateway is the most critical, because it handles all inbound calls to APIs. Therefore, it is recommended to have at least a 2-node cluster of API Gateways in a distributed setup.

Important:

Performance tuning requires you to modify important system files, which affect all programs running on the server. It is recommended to familiarize yourself with these files using Unix/Linux documentation before editing them.
The values discussed here are general recommendations. They might not be the optimal values for the specific hardware configurations in your environment. It is recommended to carry out load tests on your environment to tune App Manager accordingly.

OS-level settings

To optimize network and OS performance, configure the following settings in the /etc/sysctl.conf file of Linux. These settings specify a larger port range, a more effective TCP connection timeout value, and a number of other important parameters at the OS-level.

It is not recommended to use net.ipv4.tcp_tw_recycle = 1 when working with network address translation (NAT), such as if you are deploying products in EC2 or any other environment configured with NAT.
```
net.ipv4.tcp_fin_timeout = 30
fs.file-max = 2097152
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 1
net.core.rmem_default = 524288
net.core.wmem_default = 524288
net.core.rmem_max = 67108864
net.core.wmem_max = 67108864
net.ipv4.tcp_rmem = 4096 87380 16777216
net.ipv4.tcp_wmem = 4096 65536 16777216
net.ipv4.ip_local_port_range = 1024 65535      
```
To alter the number of allowed open files for system users, configure the following settings in the /etc/security/limits.conf file of Linux. (Be sure to include the leading * character).
```
* soft nofile 4096
* hard nofile 65535
```
Optimal values for these parameters depend on the environment.
To alter the maximum number of processes your user is allowed to run at a given time, configure the following settings in the /etc/security/limits.conf file of Linux. (Be sure to include the leading * character). Each Carbon server instance you run would require upto 1024 threads (with default thread pool configuration). Therefore, you need to increase the nproc value by 1024 per each carbon server (both hard and soft).
```
* soft nproc 20000
* hard nproc 20000
```

JVM-level settings

If one or more worker nodes in a clustered deployment require access to the management console, you would need to increase the entity expansion limit as follows in the <APPM_HOME>/bin/wso2server.bat file (for Windows) or the <APPM_HOME>/bin/wso2server.sh file (for Linux/Solaris). The default entity expansion limit is 64000.

-DentityExpansionLimit=100000

WSO2 Carbon platform-level settings

In multitenant mode, the WSO2 Carbon runtime limits the thread execution time. That is, if a thread is stuck or taking a long time to process, Carbon detects such threads, interrupts and stops them. Note that Carbon prints the current stack trace before interrupting the thread. This mechanism is implemented as an Apache Tomcat valve. Therefore, it should be configured in the <PRODUCT_HOME>/repository/conf/tomcat/catalina-server.xml file as shown below.

<Valve className="org.wso2.carbon.tomcat.ext.valves.CarbonStuckThreadDetectionValve" threshold="600"/>

The className is the Java class used for the implementation. Set it to org.wso2.carbon.tomcat.ext.valves.CarbonStuckThreadDetectionValve.
The threshold gives the minimum duration in seconds after which a thread is considered stuck. The default value is 600 seconds.