[opensuse] executing grub2 on an external drive
I have a USB system disk that currently will not boot. I currently have the USB disk loaded on my main system and would like to run grub2 to update the boot block on the USB device. I have looked at the USB grub.cfg file and it appears to match the one on my system except for the UUID. How does one execute grub2 with a target other than my system disk. Also, what is the best way to get the UUID for the partition. I scanned the output of hwinfo and the UUID on the USB drive appears to be correct, but there must be an easier way. Thanks Don -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
07.11.2015 22:43, don fisher пишет:
I have a USB system disk that currently will not boot. I currently have the USB disk loaded on my main system and would like to run grub2 to update the boot block on the USB device. I have looked at the USB grub.cfg file and it appears to match the one on my system except for the UUID. How does one execute grub2 with a target other than my system disk. Also, what is the best way to get the UUID for the partition. I scanned the output of hwinfo and the UUID on the USB drive appears to be correct, but there must be an easier way.
It is not quite clear, but assuming you want to install grub2 that looks for /grub2 on USB for its configuration, it is mount /dev/sdXN /mnt grub2-install --boot-directory=/boot /dev/sdX where /dev/sdXN is device for partition on your USB disk. It will copy grub2 files to /grub2 and bootstrap code in MBR. This code will look for /grub2 on partition N for its files, e.g. /grub2/grub.cfg. It will *not* create or update grub.cfg - you will need to write it yourself. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
On 11/07/2015 01:16 PM, Andrei Borzenkov wrote:
07.11.2015 22:43, don fisher пишет:
I have a USB system disk that currently will not boot. I currently have the USB disk loaded on my main system and would like to run grub2 to update the boot block on the USB device. I have looked at the USB grub.cfg file and it appears to match the one on my system except for the UUID. How does one execute grub2 with a target other than my system disk. Also, what is the best way to get the UUID for the partition. I scanned the output of hwinfo and the UUID on the USB drive appears to be correct, but there must be an easier way.
It is not quite clear, but assuming you want to install grub2 that looks for /grub2 on USB for its configuration, it is
mount /dev/sdXN /mnt grub2-install --boot-directory=/boot /dev/sdX
where /dev/sdXN is device for partition on your USB disk.
It will copy grub2 files to /grub2 and bootstrap code in MBR. This code will look for /grub2 on partition N for its files, e.g. /grub2/grub.cfg.
It will *not* create or update grub.cfg - you will need to write it yourself. Thanks. I believe I have the grub2 files in /boot/grub2. The drive tries to boot, then gives me a ioerror 2 message and hangs. There is something it is looking for that is not there or incorrect. I guess I will have to do a system install on the USB drive again and start from scratch. I was hoping there was a way to trick grub2 into executing on one drive while it was updating another. How do you get the UUID?
Don -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
don fisher composed on 2015-11-07 14:22 (UTC-0700):
How do you get the UUID?
Several ways, among which blkid, tune2fs and ls /dev/disk/by-uuid/. -- "The wise are known for their understanding, and pleasant words are persuasive." Proverbs 16:21 (New Living Translation) Team OS/2 ** Reg. Linux User #211409 ** a11y rocks! Felix Miata *** http://fm.no-ip.com/ -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
On 11/07/2015 04:22 PM, don fisher wrote:
How do you get the UUID?
I'm not going to anwer your question even though there is an answer to the one you've asked. You are assuming that grub2 needs a UUDi and ONLY a UUID. Well it doesn't, you can boot "by label" rather than "by uuid". For example, in my grub2/grub/cfg I have linux /vmlinuz-4.3.0-1.g7b374a4-default root=/dev/mapper/vgmain-vROOT resume=/dev/disk/by-label/SWAP splash=silent quiet showopts vga=0x31a "Mapper"? Well I'm using LVM :-) but as it happens the label of vgmain-vROOT is "ROOT132" So that could be root=/dev/disk/by-label/ROOT132 Yes, Linux file systems can be labelled. Its not just DOS ones :-) I find that labelling my disks/partitions makes life easier. Especially when I have what amounts to many copies of the same thing. Many users have multi-boot system but I also have different "/home". Under DOS the labels are "hidden file names". Its a shame that the mechanisms for Linux isn't similar so we could have 256 character labels :-) More detail than you need https://en.wikipedia.org/wiki/GUID_Partition_Table http://www.cyberciti.biz/faq/linux-modify-partition-labels-command-to-change... Well ok, theres this as well reiserfstune -l LABEL Perhaps more interesting http://unix.stackexchange.com/questions/14165/list-partition-labels-from-the... -- A: Yes. > Q: Are you sure? >> A: Because it reverses the logical flow of conversation. >>> Q: Why is top posting frowned upon? -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
08.11.2015 00:22, don fisher пишет:
On 11/07/2015 01:16 PM, Andrei Borzenkov wrote:
07.11.2015 22:43, don fisher пишет:
I have a USB system disk that currently will not boot. I currently have the USB disk loaded on my main system and would like to run grub2 to update the boot block on the USB device. I have looked at the USB grub.cfg file and it appears to match the one on my system except for the UUID. How does one execute grub2 with a target other than my system disk. Also, what is the best way to get the UUID for the partition. I scanned the output of hwinfo and the UUID on the USB drive appears to be correct, but there must be an easier way.
It is not quite clear, but assuming you want to install grub2 that looks for /grub2 on USB for its configuration, it is
mount /dev/sdXN /mnt grub2-install --boot-directory=/boot /dev/sdX
This was --boot-directory=/mnt of course; sorry!
where /dev/sdXN is device for partition on your USB disk.
It will copy grub2 files to /grub2 and bootstrap code in MBR. This code will look for /grub2 on partition N for its files, e.g. /grub2/grub.cfg.
It will *not* create or update grub.cfg - you will need to write it yourself. Thanks. I believe I have the grub2 files in /boot/grub2. The drive tries to boot, then gives me a ioerror 2 message and hangs. There is something
I do not understand it. Please take a photo when it hangs.
it is looking for that is not there or incorrect. I guess I will have to do a system install on the USB drive again and start from scratch. I was hoping there was a way to trick grub2 into executing on one drive while it was updating another.
I am not sure I understand it either. --boot-directory defines where grub is located - that is, where GRUB binaries, support files (themes etc) and grub.cfg are located. This directory need not be present on the same device as where grub bootstrap code is installed (last argument in grub-install). So mount /dev/sdb1 /mnt grub-install --boot-directory=/mnt /dev/sda is perfectly valid. It will install bootstrap code on /dev/sda and this code will look on /grub directory on /dev/sdb1 for grub.cfg and other files. Please explain what you intend to do.
How do you get the UUID?
Why do you need it? grub-install does everything for you. What you want to do with UUID? -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
On 11/07/2015 11:07 PM, Andrei Borzenkov wrote:
08.11.2015 00:22, don fisher пишет:
On 11/07/2015 01:16 PM, Andrei Borzenkov wrote:
07.11.2015 22:43, don fisher пишет:
I have a USB system disk that currently will not boot. I currently have the USB disk loaded on my main system and would like to run grub2 to update the boot block on the USB device. I have looked at the USB grub.cfg file and it appears to match the one on my system except for the UUID. How does one execute grub2 with a target other than my system disk. Also, what is the best way to get the UUID for the partition. I scanned the output of hwinfo and the UUID on the USB drive appears to be correct, but there must be an easier way.
It is not quite clear, but assuming you want to install grub2 that looks for /grub2 on USB for its configuration, it is
mount /dev/sdXN /mnt grub2-install --boot-directory=/boot /dev/sdX
This was --boot-directory=/mnt of course; sorry!
where /dev/sdXN is device for partition on your USB disk.
It will copy grub2 files to /grub2 and bootstrap code in MBR. This code will look for /grub2 on partition N for its files, e.g. /grub2/grub.cfg.
It will *not* create or update grub.cfg - you will need to write it yourself. Thanks. I believe I have the grub2 files in /boot/grub2. The drive tries to boot, then gives me a ioerror 2 message and hangs. There is something
I do not understand it. Please take a photo when it hangs.
it is looking for that is not there or incorrect. I guess I will have to do a system install on the USB drive again and start from scratch. I was hoping there was a way to trick grub2 into executing on one drive while it was updating another.
I am not sure I understand it either. --boot-directory defines where grub is located - that is, where GRUB binaries, support files (themes etc) and grub.cfg are located. This directory need not be present on the same device as where grub bootstrap code is installed (last argument in grub-install). So
mount /dev/sdb1 /mnt grub-install --boot-directory=/mnt /dev/sda
is perfectly valid. It will install bootstrap code on /dev/sda and this code will look on /grub directory on /dev/sdb1 for grub.cfg and other files.
Please explain what you intend to do.
How do you get the UUID?
Why do you need it? grub-install does everything for you. What you want to do with UUID?
I have a USB hard drive that I boot and use to keep all of my systems identical. When I did my last update, the USB drive became unbootable so I wanted to determine what was broken. The UUID appears in the grub.cfg command line as the device identifier. I now fear that the kernel modules may be out of sync with the other files in /boot/grub2. I have not had time to pursue further. Thanks -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
On 25/11/15 06:40, don fisher wrote:
On 11/07/2015 11:07 PM, Andrei Borzenkov wrote:
08.11.2015 00:22, don fisher пишет:
On 11/07/2015 01:16 PM, Andrei Borzenkov wrote:
07.11.2015 22:43, don fisher пишет:
I have a USB system disk that currently will not boot. I currently have the USB disk loaded on my main system and would like to run grub2 to update the boot block on the USB device. I have looked at the USB grub.cfg file and it appears to match the one on my system except for the UUID. How does one execute grub2 with a target other than my system disk. Also, what is the best way to get the UUID for the partition. I scanned the output of hwinfo and the UUID on the USB drive appears to be correct, but there must be an easier way.
It is not quite clear, but assuming you want to install grub2 that looks for /grub2 on USB for its configuration, it is
mount /dev/sdXN /mnt grub2-install --boot-directory=/boot /dev/sdX
This was --boot-directory=/mnt of course; sorry!
where /dev/sdXN is device for partition on your USB disk.
It will copy grub2 files to /grub2 and bootstrap code in MBR. This code will look for /grub2 on partition N for its files, e.g. /grub2/grub.cfg.
It will *not* create or update grub.cfg - you will need to write it yourself. Thanks. I believe I have the grub2 files in /boot/grub2. The drive tries to boot, then gives me a ioerror 2 message and hangs. There is something
I do not understand it. Please take a photo when it hangs.
it is looking for that is not there or incorrect. I guess I will have to do a system install on the USB drive again and start from scratch. I was hoping there was a way to trick grub2 into executing on one drive while it was updating another.
I am not sure I understand it either. --boot-directory defines where grub is located - that is, where GRUB binaries, support files (themes etc) and grub.cfg are located. This directory need not be present on the same device as where grub bootstrap code is installed (last argument in grub-install). So
mount /dev/sdb1 /mnt grub-install --boot-directory=/mnt /dev/sda
is perfectly valid. It will install bootstrap code on /dev/sda and this code will look on /grub directory on /dev/sdb1 for grub.cfg and other files.
Please explain what you intend to do.
How do you get the UUID?
Why do you need it? grub-install does everything for you. What you want to do with UUID?
I have a USB hard drive that I boot and use to keep all of my systems identical. When I did my last update, the USB drive became unbootable so I wanted to determine what was broken. The UUID appears in the grub.cfg command line as the device identifier. I now fear that the kernel modules may be out of sync with the other files in /boot/grub2. I have not had time to pursue further.
Thanks
What Andrei is saying is correct: execute the commands he shows above -- the only thing is that only *root* can execute them. All the parameters necessary for grub2 are already known and will be automatically taken care of when you execute. "grub-install.....". However, I think that there is another step missing -- but I am not sure because I have not been following this thread and so the missing step may have been already mentioned. The missing step is creating the /grub.cfg itself to meet the new situation: the command of, "grub2-mkconfig -o /mnt/sdb1/boot/grub2/grub.cfg". It may help if you first have a look at this .pdf to see what is being attempted and why: http://www.linuxidentity.com/us/down/articles/LSK_multi_distro_install_US.pd... The one thing to keep in mind is that the .pdf file has been written with Ubuntu in mind and references to "grub" are to legacy grub and not grub2 so that in some of the commands one has to substitute "grub2" for "grub". If this is making it sound like a lot of mind boggling crap, it is :-( . Why cannot people leave name of programs as they are instead of not only changing them but also using the different names (grub, grub2) within the same program! For example, Andrei shows the command to install grub2 (above) as "*grub*-install --boot-directory=/mnt /dev/sda" -- after which the commands become "*grub2*-mkconfig......" if the operating system is using grub2. But, then, that's what make Linux interesting, right? :-) . BC -- Using openSUSE 13.2, KDE 4.14.9 & kernel 4.3.0-17 on a system with- AMD FX 8-core 3.6/4.2GHz processor 16GB PC14900/1866MHz Quad Channel RAM Gigabyte AMD3+ m/board; Gigabyte nVidia GTX660 GPU -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
Basil Chupin composed on 2015-11-25 16:48 (UTC+1100):
Why cannot people leave name of programs as they are
Unlike Ubuntu and Fedora, and much like with KDE3 and KDE4, in the case of Grub(2), the openSUSE development team recognized the new/rewritten version "2" amounted to an alpha/beta/v0.x product that users would object to having foisted on them, and so included the possibility for users to choose either or both. That offering option dictates the use of a different name for one or the other. The openSUSE team opted for the different name for the newer. The new offers things many people still do not, and may never need, at a price premium they are unwilling to pay. I'm glad they made the choice they did, offering us the choice we have. I enjoy the relative simplicity of the old version, and continue to use it only even in TW and Leap. -- "The wise are known for their understanding, and pleasant words are persuasive." Proverbs 16:21 (New Living Translation) Team OS/2 ** Reg. Linux User #211409 ** a11y rocks! Felix Miata *** http://fm.no-ip.com/ -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
On 25/11/15 17:42, Felix Miata wrote:
Basil Chupin composed on 2015-11-25 16:48 (UTC+1100):
Why cannot people leave name of programs as they are Unlike Ubuntu and Fedora, and much like with KDE3 and KDE4, in the case of Grub(2), the openSUSE development team recognized the new/rewritten version "2" amounted to an alpha/beta/v0.x product that users would object to having foisted on them, and so included the possibility for users to choose either or both. That offering option dictates the use of a different name for one or the other. The openSUSE team opted for the different name for the newer.
I am not sure that I am following your argument here which seems to me to be quite unfollowable :-) . "...the openSUSE development team recognized the new/rewritten version "2" amounted to an alpha/beta/v0.x product that users would object to having foisted on them, and so included the possibility for users to choose either or both." The above just doesn't "compute" as it stands. If you were to state that it all boiled down to people who were downright stubborn not to switch from grub (legacy) to grub2 then simply say so :-) . I know that you were/are one of them :-) . However, the use of the combination of both "grub" and "grub2" in commands when creating a GRUB menu is a piece of nonsense only explainable by people with addled minds :-) .
The new offers things many people still do not, and may never need, at a price premium they are unwilling to pay. I'm glad they made the choice they did, offering us the choice we have. I enjoy the relative simplicity of the old version, and continue to use it only even in TW and Leap.
I cannot argue with you on this. I do not use UEFI in my BIOS nor do I use btfrs as my file system. But what may happen when I have to use either or when I have to dual boot with something like Windows 10 is another matter because, as I understand, one needs to use grub2 to be able to do so. I have no hassles with using grub2. It's quite simple really. I don't need to configure/write/edit my own files for grub. I simply issue a simple command of "grub2-mkconfig -o /boot/grub2/grub.cfg" and it's all done. No tears, no gnashing of teeth. But, of course, there are some people who prefer to go thru the process of editing grub menu files etc just to say that they prefer to use grub legacy -- for whatever reason, probably along the same lines as those who held that the sun rotated around the earth or that the earth is flat - but who really knows, eh? :-) BC -- Using openSUSE 13.2, KDE 4.14.9 & kernel 4.3.0-17 on a system with- AMD FX 8-core 3.6/4.2GHz processor 16GB PC14900/1866MHz Quad Channel RAM Gigabyte AMD3+ m/board; Gigabyte nVidia GTX660 GPU -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org
participants (5)
-
Andrei Borzenkov -
Anton Aylward -
Basil Chupin -
don fisher -
Felix Miata