Re: bootable failed sw raid 1 with F9

2008-06-17 Thread John Whitley

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:

[EMAIL PROTECTED] 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

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Fedora 9 - changing screen resolution with sys-config-display (or not)

2008-05-29 Thread John Whitley
Having fresh installed Fedora 9, I am struggling with changing both the 
Monitor type and the screen resolution.


System-Administration-Display-Hardware allowed ne to change the 
Monitor type to Generic LCD 1280x1024


Further attempts do not update /etc/X11/xorg.conf

Setting the monitor to 1280x1024 gave me a screen resolution of 1024x768

Attempting to change this by either 
System-Preferences-Hardware-Screen Resolution or 
System-Administration-Display-Settings, I was only offered either the 
same or lower resolutions.


Editing /etc/X11/xorg.conf to a higher resolution solved the problem.

In each case I was careful to make the change and then re-login.

Looking at Redhat Bugzilla, it appears there have been problems with 
sys-config-display since Fedora 7 although I did not suffer with this on 
numerous Fedora 8 boxes I setup.


Is this a common problem? How do others change screen resolution?

I would be grateful for advice

Regards

John Whitley

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