How to manually configure LUN’s on your redhat system

LUN detection procedure:

This topic will help you manually configure LUN’s. If you have linux drivers that does not automatically configure LUNs’s other than LUN 0, you can manually configure the other LUN’s depending on the parameters.

Detecting the LUN’s automatically when the system is started by modifying initial ram-disk(initrd).

1. Open the file /etc/modules.conf file.

2. For linux 2.4 kernels add following line:

options scsi_mod max_scsi_luns=n

For linux 2.6 kernels, add the following line:

options scsi_mod max_luns=n

where n is total number of LUN’s to probe.

3. Save the file.

4. To rebuild the current kernel issue the mkinitrd command for your operating system. By using uname -r we will come to know which kernel is currently running.

For example # uname -r

2.4.21-292-smp.

For redhat, issue the following command

cd /boot

mkinitrd -v initrd-kernel -i initrd.img kernel

5. Restart the system

6. Verify that the boot files are correctly configured for new initrd image in /boot/grub/menu.lst file.