How to use backup devices with multiple LUNs on Linux Kernel 2.6.x. (4047409)

Date: 05/10/2006
NV version: All
OS version: Linux kernel 2.6
Application version: n/a
Plugin version: n/a

Description:
When using a tape library or autoloader with multiple LUNs, NetVault doesn't recognize devices with LUN greater than 0 (zero).

Cause of Problem:
By default, the Linux kernel is configured so as it only discovers devices whose LUN is 0.

1. Edit '/etc/modprobe.conf' and add the following line -

options scsi_mod max_luns=8

2. Create boot image file with the following command

mkinitrd /boot/initrd-2.6.x.scsiluns.img `uname -r`

3a. Change bootloader configuration; if LILO is the bootloader used edit '/etc/lilo.conf' as follows (and then run /sbin/lilo) -

COMMENT OUT -
initrd=/boot/initrd-2.6.x.img
ADD -
initrd=/boot/initrd-2.6.x.scsiluns.img

3b. Change bootloader configuration; if GRUB is the bootloader used edit '/boot/grub/grub.conf' as follows -

COMMENT OUT -
initrd /boot/initrd-2.6.x.img
ADD -
initrd /boot/initrd-2.6.x.scsiluns.img

4. Restart system

NOTE: Following above steps, some system may still not recognize devices with LUN ID greater than 0 until recompiling kernel. Regarding kernel recompile, please seek the assistance of an experienced System Administrator.