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2.4. Configuring max_luns

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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

    Note

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