Booting from a SAN with multi-pathing

SUSE Linux Enterprise Server SLES Install-Boot
1

Hi,

Running SLES11sp2 on an IBM x3630m4 with Qlogic HBA card and IBM V7000 SAN.

The IBM V7000 SAN is configured and a chunk of 2TB disk is allocated to the server. The HBA configuration is working correctly. I boot the server with the SLES11sp2 CD and begin the installation. I configure the time and then SuSE probes the hardware and recognizes that “multi-path” hardware exists and I confirm that I want to use multi-pathing. In the “partition” section I configure/enable “multi-path” and /dev/sda changes to /dev/mapper/360050… 001. I then chop the disk into the following sections:
1 GB boot —> /dev/mapper/360050…001_part1
32 GB swap —> /dev/mapper/360050…001_part2
1.97TB root —> /dev/mapper/360050…001_part3

In the “booting” section I select “expert mode” and this shows that the system will boot from /dev/mapper/360050…001_part1 and the option for MBR is checked.

The system continues and finishes the installation. At the end the server needs to reboot to finalize the installation. The CMOS on the server is now set to boot from “SLES11sp2” but this fails and the installation never completes. It seems as if the MBR is never written to the SAN.

Any idea or help will be appreciated.
Regards
John

2

Hi,

The solution ended-up being quite simple but frustrating (thanks IBM) … Trash all LUNs and SAN configs. Restart the V7000 and re-create and configure the SAN for 50GB. Install SLES11 and everything works. mmmh interesting. :frowning: Delete the 50GB LUN and re-create 2.1TB LUN and try install SLES11 … failure … mmmh even more interesting. Delete the 2.1TB LUN and create 1.9TB and install SuSE and everything works. So the issue is that you cannot create a 2TB bootable LUN due to addressing.

I remember in DOS there was a memory limit of 640kb because of the 8bit OS and then in Windows 95/98 there was a limit of 2GB hard drive due to 16bit OS and now with 64bit OS you have the 2TB limit.

Anyway SuSE is up and running off the SAN so now I can virtualize my world (again) :slight_smile:

3

John Gill wrote:
[color=blue]

I remember in DOS there was a memory limit of 640kb because of the
8bit OS and then in Windows 95/98 there was a limit of 2GB hard drive
due to 16bit OS and now with 64bit OS you have the 2TB limit.[/color]

Yes, there was a 2 GB limit. If you may remember, when setting up NSS
the maximum disk/partition size was 2 GB. The size of the pool could be
larger by adding multiple such devices…

It’s always nice to know about these things before starting a project
rather than have them come up and bite you in the ***. :slight_smile:

–
Kevin Boyle - Knowledge Partner
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4

Hi John,

Thanks for posting your findings - I’ve found it very useful.

Cheers,