RHEL5 installer not seeing second HDD after RHEL6 installation
Hi, all. I'm new to the groups and hoping someone can give me some help with a peculiar problem I'm encountering.
I've currently got a pair HDDs that were used to install RHEL6 on them. When I installed RHEL6, I set up the /boot partition on a software RAID1 device (/dev/md0). The rest of my system and swap are installed to software RAID 1 devices that are also configured as logical volumes. For reasons not worth going into, I am now required to install RHEL5 instead. When I boot up on the RHEL5 installation CD (#1) and it gets to the storage partitioning step, the installer is only seeing one of two HDDs (it found /dev/sda and not /dev/sdb). My guess at this point is that it's due to the installer reading the disks and finding the previous partitioning layout on it. How do I get the installer to see both HDDs again? I'd like to start from ground zero as it were.
If I have Disk Druid delete all of the found partitions on the discovered disk and create a default layout then go back to disk druid again, will it find the second HDD?
Thanks in advance!
Responses
Hi Joseph,
I haven't looked into this too thorougly, but it's possible that an LVM pvscan is done by the installer when searching for disks. This would most likely cause the disk to be ignored due to a default LVM setting.
The below output is from the lvm.conf man page.
md_component_detection — If set to 1, LVM2 will ignore devices used as components of software RAID (md) devices by looking for md superblocks. This doesn't always work satisfactorily e.g. if a device has been reused without wiping the md superblocks first.
If you want to wipe the disk completely it might be worth zeroing the md superblock and then trying again. Only run this if you're sure there is no data on the disk that you need. It will be gone.
mdadm --stop /dev/<raid>
mdadm --remove /dev/<raid>
mdadm --zero-superblock /dev/<one path>
Hope this answers the question suffiently. If not let me know and I'll see what else could be done :)
Cheers,
Rohan
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