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Old 04-13-2007, 03:51 AM   #1
Registered: Aug 2006
Location: England
Posts: 39

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Cant see NEW LUN on RedHat Box


I'm in LUN hell at the moment.

Everytime I present a new LUN from my HP EVA to our RedHat box's, I have to reboot the
server in order to see the new LUN ?????

Im told the old Administrator used to see new luns within seconds by running the following commands:

# hp_rescan -a
# lssd

I have also ran the above commands on RedHat machines and been able to see any new presented LUNS?

What would cause hp_rescan to fail?

As I say, once I reboot the box, lssd shows the new luns and then I just pvcreate them.

Any ideas?

Old 04-13-2007, 04:06 AM   #2
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Registered: Jun 2005
Location: New Zealand
Distribution: Suse, Red Hat, AIX
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I guess it also comes down the hba drivers: if you're using qlogic try this:
Old 04-13-2007, 04:20 AM   #3
Registered: Aug 2006
Location: England
Posts: 39

Original Poster
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Yes, but we have always used the same HBA cards and drivers. So why would a driver stop working all of a sudden?

Old 08-17-2007, 04:26 AM   #4
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Registered: Jul 2007
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I have the same problem as you.
HP advice me to raise the initrd file in order to manage the problem.
Here is the mail HP send me :
In summary:
1. Modify /boot/grub/grub.conf or whatever bootloader being used to
pass the larger ram disk size as a parameter to the kernel.
Grub: add the parameter ramdisk_size=n to the kernel line.
Lilo: add new line append=ramdisk_size=n after kernel line.
2. Modify /sbin/mkinitrd and change the IMAGESIZE=n variable
to match n in bootloader change.
3. Create a new ram disk with /sbin/mkinitrd script as usual
For this configuration, use n=16000.

I have done the manipulation yet because I can't reboot the server right now but.
If you want to try, please return me the results.

Hope it will be helpfull.
Old 04-10-2009, 01:14 AM   #5
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Registered: Jun 2003
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This works on our systems (RH4 & RH5):

echo 1 > /sys/class/fc_host/host0/issue_lip # not necessarily needed -reinitializes the HBA
echo "- - -" > /sys/class/scsi_host/host0/scan
echo 1 > /sys/class/fc_host/host1/issue_lip # not necessarily needed - reinitializes the HBA
echo "- - -" > /sys/class/scsi_host/host1/scan
Old 04-29-2009, 11:13 AM   #6
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Registered: Mar 2004
Location: Littleton, CO
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I added a new LUN from IBM 8100, and the OS (RHEL 5.3) sees the new devices (fdisk -l), however when I run pvscan I do not see the new LUN. How do I get LVM to see the new LUNs?



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