FC5 RAID 1 - booting off either drive

[Craig White]

On Tue, 2006-03-28 at 08:05 -0700, Craig White wrote:
> On Mon, 2006-03-27 at 21:43 -0600, Laurence Vanek wrote:
> > Greetings -
> > 
> > To my surprise, fresh install of FC5 with RAID 1 configured at install 
> > time went without a hitch.  I have /dev/md0 defined on /boot 
> > partitions.  It boots fine with this setup.
> > 
> > I had my FC4 system setup this exact way except I found that I had to 
> > manually install grub on one of the disks to permit booting off either 
> > one if the other is down.
> > 
> > Does anyone know of a way to check for the presence of grub on each 
> > drive (obviously its on hda since it boots presently) to see if this 
> > needs to be done for FC5 also without powering down each drive in turn & 
> > attempting to boot?
> ----
> thought I should post against the right thread
> 
> just an untested thought...
> 
> bb if=/dev/sda of=/tmp/sda-bootblock.bin bs=512 count=1
> bb if=/dev/sdb of=/tmp/sdb-bootblock.bin bs=512 count=1
> 
> diff /tmp/sda-bootblock.bin /tmp/sdb-bootblock.bin
> 
> Thinking...
> 
> - substitute different values for sda/sdb as fits
> - the first 512 bytes on each drive are the boot (perhaps less, someone
> will surely correct me...it might just be the first 256 or 384 bytes)
> - if they are the same (i.e. grub has been installed on both), there
> will be no diff
> 
> otherwise...
> 
> grub-install /dev/sdb
> 
> Of course, the only way that you'll ever KNOW for sure that it's going
> to work is to do a real simulation, i.e. disconnecting one drive, then
> the other drive...
----
not only wrong thread but as Paul so correctly points out.

dd - NOT bb

I am rapidly ingesting coffee but haven't figured out a mainline method
so I am left to normal ingestion methods which apparently haven't quite
caught up to my fingers or my brain.

duh.

Sorry

Craig