Performance Tuning

This section describes some recommended performance tuning configurations to optimize WSO2 Storage Servicer. It assumes that you have set up WSO2 SS on a server running Unix/Linux, which is recommended for production deployment.

Important

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 that you carry out load tests on your environment to tune the SS 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.
```
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      
```
When we have the localhost port range configuration lower bound to 1024, there is a possibility that some processes may pick the ports which are already used by WSO2 servers. Therefore, it's good to increase the lower bound as sufficient for production, e.g., 10,000.
To alter the number of allowed open files for system users, configure the following settings in /etc/security/limits.conf file of Linux.
```
* 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
```

JVM Settings

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

-DentityExpansionLimit=100000

JDBC Pool Configuration

Within the WSO2 platform, we use Tomcat JDBC pooling as the default pooling framework due to its production ready stability and high performance. The table below indicates some recommendations on how to configure the JDBC pool using the <SS_HOME>/repository/conf/datasources/master-datasources.xml file. For more details about recommended JDBC configurations, see The Tomcat JDBC Connection Pool.

Property	Description	Recommendation
maxActive	The maximum number of active connections that can be allocated from the connection pool at the same time. The default value is `100.`	This value should match the maximum number of requests that can be expected at a time in your production environment. This is to ensure that, whenever there is a sudden increase in the number of requests to the server, all of them can be connected successfully without causing any delays. Note that this value should not exceed the maximum number of requests allowed for your database.
minIdle	The minimum number of connections that can remain idle in the pool, without extra ones being created. The connection pool can shrink below this number if validation queries fail. Default value is 0.	This value should be similar or near to the average number of requests that will be received by the server at the same time. With this setting, you can avoid having to open and close new connections every time a request is received by the server.
testOnBorrow	The indication of whether connection objects will be validated before they are borrowed from the pool. If the object validation fails, it will be dropped from the pool, and we will attempt to borrow another connection.	Setting this property to 'true' is recommended as it will avoid connection requests from failing. The `validationQuery` property should be used if testOnBorrow is set to true. To increase the efficiency of connection validation and to improve performance, `validationInterval` property should also be used.
validationInterval	To avoid excess validation, run validation at most at this frequency (time in milliseconds). If a connection is due for validation, but has been validated previously within this interval, it will not be validated again. The default value is `30000` (30 seconds).	This time out can be as high as the time it takes for your DBMS to declare a connection as stale. For example, MySQL will keep a connection open for as long as 8 hours, which requires the validation interval to be within that range. However, note that having a low value for validation interval will not incur a big performance penalty, specially when database requests have a high throughput. For example, a single extra validation query run every 30 seconds is usually negligible.
validationQuery	The SQL query used to validate connections from this pool before returning them to the caller. If specified, this query does not have to return any data, it just can't throw an SQLException. The default value is null. Example values are SELECT 1(mysql), select 1 from dual(oracle), SELECT 1(MS Sql Server).	Specify an SQL query, which will validate the availability of a connection in the pool. This query is necessary when `testOnBorrow` property is true.

When it comes to web applications, users are free to experiment and package their own pooling framework such BoneCP.

Setting the thread execution limit for multitenant mode

In multitenant mode, the 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 <SS_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 name used for the implementation. This must be set to org.wso2.carbon.tomcat.ext.valves.CarbonStuckThreadDetectionValve.
The threshold gives the minimum duration in seconds after which a thread is considered stuck. Default value is 600 seconds.