User:Rituraj Cool

Configuring a QLogic adapter on Linux

This topic describes QLogic adapter settings that can be changed based on the kernel, distribution, and IBM server hardware that you are attaching to the DS8000®. It also describes modifications to configuration parameters that you can change if you receive errors when you are running the Linux operating system on an Intel host that is attached with a QLogic adapter.

Before you proceed, determine the kernel version of the Linux distribution that you running.

Type the uname -r command to display the kernel version that you are running.

The output displays 2.4.x or 2.6.x, where x represents the maintenance and fix level for the installed distribution. For multipath solutions that use an IBM SDD or DM Multipath, you must disable the QLogic failover mechanism. Complete these steps to disable the failover mechanism.

If the driver version has a -fo extension, the failover driver is currently installed and you must disable the driver. If the driver is not installed, you do not need to complete these steps. For 2.4 kernels, edit the /etc/modules.conf file. Add the following line to the file: options qla2300 qla2xfailover=0.

For 2.6 kernels, edit the /etc/modprobe.conf or the /etc/modprobe.conf.local file. Add the following line to the file: options qla2xxx qla2xfailover=0.

For Qlogic adapter cards, you must add the following line to the /etc/modprobe.conf (for 2.6 kernels) or to the /etc/modules.conf (for 2.4 kernels) file if it is not already there.

Edit the /etc/modprobe.conf file. If the value options qla2xxx ql2xmaxqdepth=16 is not present, add it and save the configuration file. Use your normal procedure to reload the driver settings. For example, use the modprobe -r command to remove a driver and the modprobe command to install a driver.

For host systems that will be performing remote mirror and copy or Flash Copy functions, modify the timeout values to prevent I/O errors from occurring. The qfull_retry_count option (available for 2.4 kernels only) defines the number of times that a QLogic adapter card retries a command if the queue is full. The default for this option is 16. Perform the following steps to increase the timeout value to 32.

For 2.4 kernels, edit /etc/modules.conf. If the value of the qfull_retry_count option is not 32, change it to 32 and save the configuration file. If the option does not exist, add the following line: options qla2xxx qfull_retry_count=32. Use your normal procedure to reload the driver settings. For example, use the host system command modprobe -r to remove the driver and use the modprobe command to install the driver.

Note: If your QLogic driver loads at system start, run the mkinitrd command to build a new ramdisk device to reflect this change.