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Old 03-08-2010, 09:20 AM   #1
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Where in Device Mapper is the unique long WWID or UID of the LUN virtual disk stored?

Hello all. I'm having problems not making SAN disks bootable and working fine. But when I clone the disk from a working system it's assigned a brand new UID (like a mac address) at the SAN level and that cannot be changed. Somehow Device Mapper the native MPIO is supposed to be smart enough to reconfigure but it's not working. There is a multipath config file and a bindings file but changing or editing those makes no difference. Somewhere in the OS and mpio it's saving the long UID number of that old boot lun and you cannot boot to the new one unless you edit files and switch OFF multipath on boot. Then the new lun boots and works fine. The ONLY difference being the new virtual disk or LUN has a slightly different long UID number or WWID world wide ID. This WWID or UID long number cannot be changed at the hardware level. So if we ever plan on using the native MPIO for bootable SAN disks we will have to solve this problem. I'm sure there will be a place we can edit or reconfigure MPIO to reflect the new UID and problem will be solved. The issue is finding that needle in the haystack.

Any Ideas?

Old 03-08-2010, 09:40 AM   #2
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udev rules ?


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