Setting The Kernel.panic Tunable; Optimizing Llt Media Speed Settings On Private Nics; Guidelines For Setting The Media Speed Of The Llt Interconnects - Symantec Veritas Cluster Server Installation Manual

48 Preparing to install VCS
Performing preinstallation tasks

Setting the kernel.panic tunable

Optimizing LLT media speed settings on private NICs

Guidelines for setting the media speed of the LLT interconnects

By default, the kernel.panic tunable is set to zero. Therefore the kernel does not
reboot automatically if a node panics. To ensure that the node reboots
automatically after it panics, this tunable must be set to a non zero value.
To set the kernel.panic tunable
1 Set the kernel.panic tunable to a desired value in the /etc/sysctl.conf file.
For example, kernel.panic = 10, will assign a value 10 seconds to the
kernel.panic tunable. This step makes the change persistent across reboots.
2 Run the command:
sysctl -w kernel.panic=10
In case of a panic, the node will reboot after 10 seconds.
For optimal LLT communication among the cluster nodes, the interface cards on
each node must use the same media speed settings. Also, the settings for the
switches or the hubs that are used for the LLT interconnections must match that
of the interface cards. Incorrect settings can cause poor network performance or
even network failure.
Review the following guidelines for setting the media speed of the LLT
interconnects:
Symantec recommends that you manually set the same media speed setting
on each Ethernet card on each node.
If you have hubs or switches for LLT interconnects, then set the hub or switch
port to the same setting as used on the cards on each node.
If you use directly connected Ethernet links (using crossover cables), set the
media speed to the highest value common to both cards, typically
100_Full_Duplex.
Symantec does not recommend using dissimilar network cards for private
links.
Details for setting the media speeds for specific devices are outside of the scope
of this manual. Consult the device s documentation for more information.