Re: Added SATA drive, now it won't boot

[Tracy Reed]

Simon Hobson said:
> What does your grub.conf have for device names ?

Thank you very much for your reply!

I'm running CentOS 7 so I have a /etc/grub2.conf which contains, among a
lot of other code which I do not yet understand, this code which I
believe is the relevant part with the first part being the OS I intend
to boot and the second being a rescure mode, both having the same
problem:

### BEGIN /etc/grub.d/10_linux ###
menuentry 'CentOS Linux (3.10.0-327.el7.x86_64) 7 (Core)' --class centos 
--class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 
'gnulinux-3.10.0-327.el7.x86_64-advanced-28cfb170-d49b-4629-b624-5cdfb83ec572' {
        load_video
        set gfxpayload=keep
        insmod gzio
        insmod part_msdos
        insmod xfs
        set root='hd0,msdos1'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint='hd0,msdos1'  
28cfb170-d49b-4629-b624-5cdfb83ec572
        else
          search --no-floppy --fs-uuid --set=root 
28cfb170-d49b-4629-b624-5cdfb83ec572
        fi
        linux16 /boot/vmlinuz-3.10.0-327.el7.x86_64 
root=UUID=28cfb170-d49b-4629-b624-5cdfb83ec572 ro crashkernel=auto rhgb quiet
        initrd16 /boot/initramfs-3.10.0-327.el7.x86_64.img
}
menuentry 'CentOS Linux (0-rescue-97c498c783b540e38e76e32bb2b24a1a) 7 (Core)' 
--class centos --class gnu-linux --class gnu --class os --unrestricted 
$menuentry_id_option 
'gnulinux-0-rescue-97c498c783b540e38e76e32bb2b24a1a-advanced-28cfb170-d49b-4629-b624-5cdfb83ec572'
 {
        load_video
        insmod gzio
        insmod part_msdos
        insmod xfs
        set root='hd0,msdos1'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint='hd0,msdos1'  
28cfb170-d49b-4629-b624-5cdfb83ec572
        else
          search --no-floppy --fs-uuid --set=root 
28cfb170-d49b-4629-b624-5cdfb83ec572
        fi
        linux16 /boot/vmlinuz-0-rescue-97c498c783b540e38e76e32bb2b24a1a 
root=UUID=28cfb170-d49b-4629-b624-5cdfb83ec572 ro crashkernel=auto rhgb quiet
        initrd16 /boot/initramfs-0-rescue-97c498c783b540e38e76e32bb2b24a1a.img
}
if [ "x$default" = 'CentOS Linux (3.10.0-327.el7.x86_64) 7 (Core)' ]; then 
default='Advanced options for CentOS Linux>CentOS Linux (3.10.0-327.el7.x86_64) 
7 (Core)'; fi;
### END /etc/grub.d/10_linux ###

So we can see that it sets root to 'hd0,msdos1' but then it goes to
search by uuid. I have verified that hd0,msdos1 is correct *and* the
uuid is correct also. From probing around with the grub command line I
can verify that the drive number assignments do not change when the SATA
disk is added or removed. The NVMe device which the OS and grub were
installed to are always hd0. I have booted the machine the the SATA
drive in and with it out. It only boots properly with the drive out. But
the NVMe device and OS partition is always hd0,msd0s1.

I have verified using blkid in the booted OS and by manually typing the
above search command on the grub command line that the above uuid is on
the NVMe OS partition which is hd0,msdos1.

I have tried removing all traces of hd0,msdos1 from the config to make
it rely only on UUID and it still doesn't boot.

> If it's using names like sda1 or (hd0,0) etc then it's probably because
> the devices as seen by Grub have moved and sda is now sdb and hd0 is now
> hd1.  If you can get to the grub menu, then you should be able to edit a
> menu entry before trying to boot it and change the device names to suit.
> Once you've booted - you may need to boot to single user mode and edit
> your /etc/fstab file as well - then you can update grub to get the new
> device names.  This is the sort of thing that UUIDs were designed to get
> around - it doesn't matter what order the devices are found in, Grub and
> mount will find the right disk/partition by it's UUID. Personally I
> prefer filesystem labels (once you've had to type a couple of UUIDs to
> get a system to boot you'll know why), but Debian doesn't support that
> as an option for Grub.

I've also tried changing the device name to (hd1,msdos1) and other
things. No go. I can use the ls command like ls
(hd0,msdos1)/boot/vmlinuz etc. and see the proper files where they
should be on hd0,msdos1. But if I then try to boot it with the SATA
drive installed it won't boot, I simply get the dreaded blinking cursor
in the upper left. 

Any other ideas?

-- 
Tracy Reed

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