Installation guide

4. When the cluster is configured and running, verify that the node turns off immediately when

fenced.

Note

You can fence the node with the fence_node command or Conga.

Example 2.12. Kernel Boot Command Line with acpi=off Appended to It

# grub.conf generated by anaconda

# Note that you do not have to rerun grub after making changes to this file

# NOTICE: You have a /boot partition. This means that

# all kernel and initrd paths are relative to /boot/, eg.

# root (hd0,0)

# kernel /vmlinuz-version ro root=/dev/VolGroup00/LogVol00

# initrd /initrd-version.im g

#boot=/dev/hda

default=0

timeout=5

serial --unit=0 --speed=115200

terminal --timeout=5 serial console

title Red Hat Enterprise Linux Server (2.6.18-36.el5)

root (hd0,0)

kernel /vmlinuz-2.6.18-36.el5 ro root=/dev/VolGroup00/LogVol00

console=ttyS0,115200n8 acpi=off

initrd /initrd-2.6.18-36.el5.im g

In this example, acpi=off has been appended to the kernel boot command line — the line starting

with "kernel /vmlinuz-2.6.18-36.el5".

2.4. Configuring max_luns

If RAID storage in your cluster presents multiple LUNs (Logical Unit Numbers), each cluster node must

be able to access those LUNs. T o enable access to all LUNs presented, configure m ax_luns in the

/etc/m odprobe.conf file of each node as follows:

1. Open /etc/m odprobe.conf with a text editor.

2. Append the following line to /etc/modprobe.conf. Set N to the highest numbered LUN that is

presented by RAID storage.

options scsi_mod max_luns=N

For example, with the following line appended to the /etc/m odprobe.conf file, a node can

access LUNs numbered as high as 255:

options scsi_mod max_luns=255

3. Save /etc/m odprobe.conf.

4. Run m kinitrd to rebuild initrd for the currently running kernel as follows. Set the kernel

variable to the currently running kernel:

Red Hat Enterprise Linux 4 Cluster Administration