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. To enable access to all LUNs presented, configure max_luns in the /etc/modprobe.conf file of each node as follows:
  1. Open /etc/modprobe.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/modprobe.conf file, a node can access LUNs numbered as high as 255:
    options scsi_mod max_luns=255
  3. Save /etc/modprobe.conf.
  4. Run mkinitrd to rebuild initrd for the currently running kernel as follows. Set the kernel variable to the currently running kernel:
    # cd /boot
    # mkinitrd -f -v initrd-kernel.img kernel
    For example, the currently running kernel in the following mkinitrd command is 2.6.9-34.0.2.EL:
    # mkinitrd -f -v initrd-2.6.9-34.0.2.EL.img 2.6.9-34.0.2.EL


    You can determine the currently running kernel by running uname -r.
  5. Restart the node.