Re: bootable failed sw raid 1 with F9

Christopher K. Johnson wrote:
jrw wrote:
Sander Hoentjen wrote:
Hi list,

For the first time in my life i tried to install Fedora with sw raid.
See below what went wrong.

Here is what I did:
Start with 2 empty 500GB sata disks.
Make sure nvraid is turned off in my BIOS.
Start an F9 install, creating 2 sw RAID partitions: md0 and md1.
md0 is 100MB and has an ext3 /boot.
md1 has the rest of the space and is LVM.
In the lvm I have created the rest of my partitions.

Install went great, after reboot my system booted fine, so far so good.
I then shutdown my system, pulled out a disk and started again. I got
the message "GRUB Hard Disk Error". So I shut down, plugged the disk
back in, pulled out the other one and started again. This time I was met
by a GRUB shell, no boot logo, no idea what to do (no menu).
Shutdown again, replug the disk, start again, get on IRC, type:
grub
root (hd0,0)
setup (hd0)
root (hd1,0)
setup (hd1)

After that: reboot minus 1 disk. I can see grub, with logo and boot
options. It starts ok, i even get rhgb for a second and then I see:
"fsck.ext3: Invalid argument while trying to open /dev/md0"
I can go into a maintenance shell and when I do cat /proc/mdstat is see:
md0 : inactive sda1[0](s)

"mdadm --assemble /dev/md0" turns it active again, but well I have no
idea how I can continue normal boot, if it is even possible.

So this is my story, now my questions:
- Did I do anything wrong? I performed the installation twice, with both
times the same result.
- Is this a bug somewhere? Do other people get the same or better
results?
- Is there anything I can do to fix this?

Thanks for reading this far,

Sander


I have already experienced this problem and raised a report on Redhat bugzilla (no. 450722) although there has been no response to it so far. I spent some time pinning the problem down to Fedora 9, (it is OK on Fedora 8 plus updates).

Chances are excellent that the initial problem was grub not writing mbr correctly on both disks of the mirror. And when you did so in your interactive grub session, I believe you created a dependency on both disks being present through the use of root (hd1,0) - in effect saying look for /boot on the first partition of the second disk.

The subsequent problem with the mirror being broken may have been caused by the process of booting on one disk, not both, depending on the exact sequence of disk removal versus boots. The raid superblock would be updated on one disk, and be stale on the other, and it is appropriate that you had to re-add the stale disk afterward.

Although this should definitely be addressed as a bug in the installation process, it can also be dealt with pro-actively when booted on the newly installed system and once synchronization of mirrors backing /boot has completed.

If your grub.conf notes use of root (hd0,0), and the md (md0 in your case) for that is mirrored on disks sda and sdb:
[root@myhost]# grub
grub> device (hd0) /dev/sdb
grub> setup (hd0)
grub> quit

The difference is that here we are saying to grub, pretend the second disk is your first disk, and then write mbr for a root on this disk accordingly.

Be aware that once you boot on one disk only the raid superblocks on mirrors there are updated and no longer match those on the removed disk, thus you will need to re-synchronize your mirrors when booted with both disks present again.

When I had the problem, I had already run grub as you suggest ( using hd0) on both /dev/sda and /dev/sdb, and had gone through the process of removing dev/sdb, booting onto /dev/sda successfully, re-booting with both /dev/sda and /dev/sdb, and re-building the mirrors with mdadm --add. I repeated this cycle on Fedora 8 install, Fedora 8 plus updated kernel, Fedora 8 plus all updates successfully. I only experienced the problem either after a Fedora 9 install, or updating from Fedora 8 to Fedora 9.


John Whitley

--
fedora-list mailing list
fedora-list@xxxxxxxxxx
To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list

Relevant Pages

  • Re: Just installed Windows XP SP2 - it assigned drive letter F: - How to change to C:?
    ... I created a slipstream Windows-XP SP3 install disk to simplify ... the Windows installer finds a previous install, ... original Grub with 3 OS's. ...
    (microsoft.public.windowsxp.help_and_support)
  • Re: fedora-list Digest, Vol 8, Issue 362 (Out of office reply.)
    ... Subject: FC1 Users: Sample yum.conf for Fedora Legacy Updates ... However, more importantly the same problems that beset 1.0 PR1 also beset 1.0 RC1: namely, you cannot install extensions or add search engines as an ordinary user. ... I have to swap between Disk 1 and Disk 2>when I boot-up my PC. ... It is very inconvenient so I>want to setup dual-boot such that I am able to select>the OS at the boot-up time and, in the futre, I can>always switch back to single boot with Windows XP disk>only. ...
    (Fedora)
  • Re: GRand Unified Boot misery and Fedora Core 4
    ... > And grub sucks. ... > people, but then so does Windows, would you argue that Windows is ... You already installed Win98SE with large disk support, ... thread, get rid of the "hdd=ide-scsi" in your Fedora boot stanza, reboot, ...
    (comp.os.linux.setup)
  • Re: GRand Unified Boot misery and Fedora Core 4
    ... > And grub sucks. ... > people, but then so does Windows, would you argue that Windows is ... You already installed Win98SE with large disk support, ... thread, get rid of the "hdd=ide-scsi" in your Fedora boot stanza, reboot, ...
    (linux.redhat.install)
  • Re: Dual Boot Problem
    ... >>screen, not grub. ... > Not being able to boot the install afterwards does lead to shelving the ... Both Windows and Fedora are on IDE ... drives though, so I'm not sure whats going on. ...
    (Fedora)