Replying to both.

I am switching from prefork to worker.

The link that I posted is useful but I have two questions.

1. The number of threads for a core is 200 irrespective of the number of hardware threads or the core architecture. How ? Is this a general measure ?

2.  Longer question that might require a separate thread ? What other RHEL OS parameters need to be tuned to support this type of load.

This is a JBoss tuning tip. I am cautious because a supporting OS parameter should not cause failure. I am going to adopt a capacity planning technique using concurrent users, think time analysis etc. but at this time the tuning should include OS parameters also. Any suggestions ?

This may be an indication that there is a need to increase the number of file descriptors on the machine. On linux the command 'ulimit -n' can be used to check the total number of file descriptors. To bump up the total number for file descriptors user and system, follow these steps:

Edit /etc/security/limits.conf and add the lines: * soft nofile 1024 * hard nofile 65535

Edit /etc/pam.d/login, adding the line: session required /lib/security/pam_limits.so

The system file descriptor limit can be increased by setting "fs.file-max" in the file "/etc/sysctl.conf". To set the limit to 65535 use echo "fs.file-max = 65535" >> /etc/sysctl.conf

Increase default socket send/receive buffer

 

 

 

 

 

 

sysctl -w net.core.rmem_default=262144

(default socket receive buffer)

 

 

sysctl -w net.core.wmem_default=262144

(default socket send buffer)

 

 

sysctl -w net.core.rmem_max=262144

(max socket receive buffer)

sysctl -w net.core.wmem_max=262144

(max socket send buffer size)