On Tue, 2006-03-28 at 20:20 -0600, Laurence Vanek wrote: > Craig White wrote: > > 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 > > > > > Followed your suggestion. Boot sectors were NOT the same size on hda & > hdc (hdd is my CD-RW). Same deal as with FC4. I installed grub on my > second drive (hdc) using: > > #grub > grub>root (hd1,0) > grub>setup (hd1) > grub>quit > > powered down, unplugged hda & VIOLA! (it boots). > > Thanks for the help. ---- sure thing - just wondering (for completeness and all) - in case anyone looks at the archives... if you do... dd if=/dev/hda of=/tmp/hda-512.bin bs=512 count=1 dd if=/dev/hdc of=/tmp/hdc-512.bin bs=512 count=1 diff /tmp/hda-512.bin /tmp/hdc-512.bin do they match? (ie...diff comes up empty?) How about as Aaron suggested...466 bytes... dd if=/dev/hda of=/tmp/hda-466.bin bs=466 count=1 dd if=/dev/hdc of=/tmp/hdc-466.bin bs=466 count=1 diff /tmp/hda-466.bin /tmp/hdc-466.bin do they match? I can see a lot of occasions where the partition tables might not match on the hard drives (such as Dell's utility partition being on /dev/hda but not /dev/hdc or different brand drives, etc.)... Craig
