OS-level settings

When it comes to performance, the OS that the server runs plays an important role.

If you are running MacOS Sierra and experiencing long startup times for WSO2 products, try mapping your Mac hostname to 127.0.0.1 and ::1 in the /etc/hosts file as described. For example, if your Macbook hostname is "john-mbpro. local", then add the mapping to the canonical 127.0.0.1 address in the /etc/hosts file, as shown in the example below.

127.0.0.1 localhost john-mbpro.local

Following are the configurations you can apply to optimize OS-level performance:

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
```