Performance Tuning

This section describes some recommended performance tuning configurations to optimize the ELB. It assumes that you have set up the ELB on a server running Unix/Linux, which is recommended for a production deployment.

Performance tuning requires you to modify important system files, which affect all programs running on the server. We recommend you to familiarize yourself with these files using Unix/Linux documentation before editing them.
The parameter values we discuss below are just examples. They might not be the optimal values for the specific hardware configurations in your environment. We recommend you to carry out load tests on your environment to tune the ELB accordingly.

OS-level settings

To optimize network and OS performance, configure the following settings in /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 /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 /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
```

Memory settings

Memory allocated for ELB should be increased to the following. Note that you need to modify the <ELB_HOME>/bin/wso2server.sh file to make this change.

-Xms1500m -Xmx3000m
-XX:PermSize=256m -XX:MaxPermSize=512m

In passthru properties file, we have:

worker_pool_size_core=400
worker_pool_size_max=500
io_buffer_size=16384