Red Hat Bugzilla – Bug 163460
Installation failed on RAID setup (GRUB error 15 and failed to mount /)
Last modified: 2008-07-24 16:58:29 EDT
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Description of problem:
I installed a machine with RHEL4 ES on a machine with a pair of IDE discs that I configured using software RAID, the install appeared successful until the reboot where I hit a GRUB error 15; having fixed that it then had problems mounting the root filesystem RAID.
The discs had old installs on previously, so the first thing I did in the graphical installer was delete all partitions; the pair of discs were not identical but close in size.
I created three pairs of partitions - using the individual partition creation in the graphical installer, assigning each one as RAID;
one for /boot (250MB)
one for swap (2GB)
one for / (about 34GB)
The partitions were created with fixed sizes.
I then went and told it to create three mirrored RAIDs.
The boot gave a GRUB error 15 (after or at loading stage 1.5?) - at that point I
booted off the install CD, used mdadm to bring up the RAID and then used the grub command line and grub's 'setup' command to reinstall grub; so that fixed that. (I didn't change the initrd or menu.lst file - so all the initrd setup and root fs paths were as produced by the installer).
Now on boot it complained it couldn't mount / ; and looking at the boot messages
I think it had failed to autostart one of the three RAIDs.
Using the rescue mode on the install CD it would give me the option of mounting md1 as the root filesystem, but once selected it would say there was an error and drop me to a shell. (It listed md1 twice actually for some reason).
It looks like the GUI parttioning had decided to create the partitions on the two discs in opposite orders; i.e.
the md0 raid was hda1, hdc1
md1 raid hda3, hdc2
md2 raid hda2, hdc3
(They were definitely mismatched like this - I'm not sure if it was md1 that
So I attacked it with fdisk and swapped the partition numbering round, and a
few more boots I was OK.
I sugges that autodetection of the RAID for / without any checking that ensures that it finds the right RAID is not robust enough - wouldn't it be better to assemble the / RAID given the unique IDs in the RAID parts so that even if another RAID disappears then at least / is there and you have a bootable system?
P.S. *please* do something about the 'time left to install' approximation - it is hopelessly optimistic, it spent 2 hours or more at '50 mins remaining'
Version-Release number of selected component (if applicable):
Just cross-referencing this:
Bug #191449 NEW install grub incorrect when /boot is a RAID1 device
Bug #170575 NEW grub fails on one of two sata disks of raid1 set during i...
>> Bug #163460 NEW Installation failed on RAID setup (GRUB error 15 and fail...
Bug #160563 NEW "grub-install /dev/md0" does not install on second disk i...
Bug #114690 CLOSED/RAWHIDE grub-install won't install to RAID 1
This has been tested with rhel4u7 and the reported bug no longer appears. Please
try installing the latest release to see if it works for you. If you encounter
the problem again, feel free to reopen this bug with the information.