Setting Performance Tuning Values

The following sub-sections explain how the recommended performance tuning values can be set:

Setting the file descriptor count

The maximum file descriptor limit should be 2097152. If you wish to check the file descriptor count, execute the following command: sysctl fs.file-nr

The above command will return counts of file descriptors in the following format: <in_use> <unused_but_allocated> <maximum>

Follow the instructions below to increase the file descriptor count:

Log in as a root user.
Open the sysctl.conf file, which is in the /etc/ directory.
Add or edit the following line in the file as follows and reboot the system.
fs.file-max = 2097152

Setting maximum open file descriptor limits

Follow the instructions below to set the maximum open file descriptor limits in Linux:

Log in as a root user.
Open the limits.conf file, which is in the /etc/security/ directory.
Add or edit the following two lines in the file.
```
* soft nofile 4096
* hard nofile 65535
```
- An asterisk * has been added at the start of the entry to set the maximum open file descriptor limit for all the users. However, if you wish to set the open file descriptor limit only for a specific user, enter that respective user's username instead of an asterisk.
- The soft limit defines the minimum number of file handles or open files that the users will have after they log in.
- The hard limit defines the maximum number of file handles or open files that the users will have after they log in.
  
  If you encounter an error message about running out of file handles, then the hard limit can be increased.

Setting JVM memory allocation limits for WSO2 EMM

Follow the instruction below to change the JVM memory allocation limits for WSO2 EMM:

Navigate to the <EMM_HOME>/bin/ directory and open the wso2server.sh file.
Locate the following entry:
-Xms256m -Xmx1024m -XX:MaxPermSize=256m
Update the above entry as follows and save the wso2server.sh file.
-Xms2048m -Xmx2048m -XX:MaxPermSize=1024m

The Java Virtual Machine (JVM) memory allocation pool limits have been described as follows:

- -Xms - This specifies the initial memory allocation pool for a JVM.
- -Xmx - This specifies the maximum memory allocation pool for a JVM.
- -XX:MaxPermSize - The permanent space is where the classes, methods, internalized strings, and similar objects used by the VM are stored and never deallocated. This defines the maximum space that will be allocated as permanent space.
  
  The default JDK value is assigned to XX:MaxPermSize from JDK 8 and above. Therefore the value you assign to XX:MaxPermSize will not be taken only if you are running EMM on JDK 8 and above.