[gentoo-user] How to set up drive with many Linux distros?
For many years, I've used a hard drive on which I have 8-10 Linux distros installed -- each in a separate (single) partition. There is also a single swap partition (used by all of the different Linux installations). There is also a small partition devoted only to the "master" instance of Grub that lives in the MBR and the space between the MBR and the first partition (the drive uses a DOS disklabel). That master instance of Grub has a menu which contains entries which "chainload" each of the other partitions. For many years, this worked great. All of the various distro installers offered the option of installing the bootloader in the MBR (e.g. /dev/sda) or in a partition (e.g /dev/sdaN). I would tell the installer to install the bootloader in the root partition, and everything "just worked". However, the choice to install bootloaders in partitions instead of the MBR has been removed from most (all?) of the common installers. This forces me to jump through hoops when installing a new Linux distro: 1. Back up the MBR and gap between the MBR and the first partition. 2. Let the installer install it's bootloader (seems it's always grub these days) in the MBR. 3. Boot into the newly installed Linux. 4. Manually install grub in the root partition (e.g. /dev/sdaN) using the --force option to tell grub to use blocklists to find it's files. 5. Find those grub files and lock them so they can't be moved. 6. Restore the MBR/gap backup from step 1. It seems like there should be a better way to do this. One might hope that UEFI offers a solution to this problem. Google has found me others asking the same question but no real answers. Is there an easier way to do this? -- Grant
[gentoo-user] Re: How to set up drive with many Linux distros?
On 2024-02-22, Wol wrote: > On 22/02/2024 19:17, Grant Edwards wrote: > >> However, the choice to install bootloaders in partitions instead of >> the MBR has been removed from most (all?) of the common installers. >> This forces me to jump through hoops when installing a new Linux >> distro: > > File a bug! LOL, good one! As if a normal person filing a bug with RedHat or Ubuntu actually accomplishes anything. I'll tell them to make systemd optional while I'm at it. > If that's true, it basically borks any sort of dual boot, unusual disk > layout, whatever. Yep, it does. The answer from is: You should really just (shut up and) install 's (obviously superior) bootloader in the MBR. It will auto-detect (some of) the other already installed (obviously inferior) OSes, and will add (some subset of) them to the boot menu that will (sometimes) allow you to boot them (maybe -- if you kneel, bow your head and ask nicely). > Last time I installed SUSE, it trashed my boot totally because it > didn't recognise my disk stack, failed to load necessary drivers, > and worse trashed my gentoo boot too... > > Cue one big rescue job to get the system up and working again. At > least it was only the boot that was trashed. I've been reading up on UEFI, and it doesn't seem to be any better. People complain about distro's stomping on each other's files in the ESP partiton and multiple distro's using the same name in the boot slots stored in NVM. And then the boot choice order changes (though it may not be apparent to the naked eye) when one of the distros decides to update/reinstall its boot stuff. -- Grant
Re: [gentoo-user] Re: How to set up drive with many Linux distros?
On 22/02/2024 21:45, Grant Edwards wrote: I've been reading up on UEFI, and it doesn't seem to be any better. People complain about distro's stomping on each other's files in the ESP partiton and multiple distro's using the same name in the boot slots stored in NVM. And then the boot choice order changes (though it may not be apparent to the naked eye) when one of the distros decides to update/reinstall its boot stuff. At least if you use UEFI *as* your bootloader, then that won't happen. That assumes you're using UEFI, though! In which case, 's bootloader doesn't get a look-in. As for "'s obviously superior bootloader", well is using the exact same boot-loader, and when IT installs, how is it going to be able to boot if it can't call 's boot loader because it's just trashed it by overwriting it? To me, you seem to be describing the *default* installer setup, that's been there for ever. Last I installed SUSE, iirc I had to specify "advanced bootloader installation", most of who's options I didn't even understand!, but it did do what I told it to (apart from not recognising my weird disk stack!). If you can find, and understand!, that advanced options, I think you'll find you can do what you want. Cheers, Wol
Re: [gentoo-user] How to set up drive with many Linux distros?
On 22/02/2024 19:17, Grant Edwards wrote: However, the choice to install bootloaders in partitions instead of the MBR has been removed from most (all?) of the common installers. This forces me to jump through hoops when installing a new Linux distro: File a bug! If that's true, it basically borks any sort of dual boot, unusual disk layout, whatever. Last time I installed SUSE, it trashed my boot totally because it didn't recognise my disk stack, failed to load necessary drivers, and worse trashed my gentoo boot too ... Cue one big rescue job to get the system up and working again. At least it was only the boot that was trashed. Cheers, Wol
[gentoo-user] Re: How to set up drive with many Linux distros?
On 2024-02-22, Wol wrote: > On 22/02/2024 21:45, Grant Edwards wrote: >> I've been reading up on UEFI, and it doesn't seem to be any >> better. People complain about distro's stomping on each other's files >> in the ESP partiton and multiple distro's using the same name in the >> boot slots stored in NVM. And then the boot choice order changes >> (though it may not be apparent to the naked eye) when one of the >> distros decides to update/reinstall its boot stuff. > > At least if you use UEFI *as* your bootloader, then that won't > happen. That assumes you're using UEFI, though! According to what I've read UEFI isn't a bootloader. It's a boot manager which can load and run EFI bootloaders (of which there can be multiple installed). > In which case, 's bootloader doesn't get a look-in. Yes, AFAICT, it does (sometimes?). When you install under UEFI it installs EFI bootloader files (either kernels wrapped in EFI bootloader executables or the grub EFI bootloader) in the EFI Systgem Partition (ESP), and then adds one or more entries in the EFI NVM that points to those files (or something like that). The Linux UEFI systems I have all still use grub2 (which gets written to the ESP). It's entirely possible for one distro to overwrite files in the ESP that belong to other distros. I've read multiple complaints about exactly that when trying to do multi-boot with UEFI. In practice it's just like the fight over who owns the MBR and the DOS disklable gap. One recipe I read about for doing what I wanted to do with UEFI involved installing a Linux distro (didn't really matter which), then installing rEFInd. After that, some manual renaming and deleting of the files in the ESP was required. Then he started installing various distros. After each distro installation, the author had to re-install rEFInd, and after many of them he had to manually remove or rename files in the ESP (or adjust the rEFInd config file). And in the end, he ended up with multiple menu entries (for different installations) that had identical names. It was more complicated and difficult than my current scheme. > As for "'s obviously superior bootloader", well > is using the exact same boot-loader, and when IT installs, how is it > going to be able to boot if it can't call 's boot > loader because it's just trashed it by overwriting it? In my experience, 's bootloader does not boot other installations by calling other bootloaders. It does so by rummaging through all of the other partitions looking for kernel images, intird files, grub.cfg files, etc. It then adds menu entries to the config file for 's bootloader which, when selected, directly load the kernel image and initrd from those other partitions. Sometimes, it works -- at least until those other installations get updated without the knowlege of the distro that currently "owns" the MBR's bootloader config. Then it stops working until you tell that bootloader to re-do it's rummaging about routine. > To me, you seem to be describing the *default* installer setup, that's > been there for ever. Last I installed SUSE, iirc I had to specify > "advanced bootloader installation", most of who's options I didn't even > understand!, but it did do what I told it to (apart from not recognising > my weird disk stack!). So SuSe still allows you to install grub to a partition instead of MBR? That's encouraging. RH and Ubuntu used to allow that, but AFAIK, now they do not. > If you can find, and understand!, that advanced options, I think > you'll find you can do what you want. I'd welcome pointers to where those advanced options are in the RH and Ubunutu installers -- I've searched everywhere I can think of. Various things Google has found lead me to believe that they no longer support installing grub in a partition. I guess I'll stick with my current setup. Or perhaps I'll switch from a DOS disklabel to a GPT disklabel. Instead of backing up and restoring the MBR and the gap, I would backup and restore the MBR and the BIOS boot partition. And I could use UUIDs and partition labels.
Re: [gentoo-user] Re: How to set up drive with many Linux distros?
Hello! I guess most (all) of the distro's you are talking about use GRUB (or at least they allow to do it). If that's true, I'm pretty sure you can happily let them overwrite the GRUB in MBR as many times as they want, since it's the same (or just probably minor version differences) bootloader. Just make a copy of /boot/grub/grub.cfg and make sure it's the same on every partition. Or, even better, if that's possible right now, make a common /boot partition and after installing the new distro just merge the (probably new) /boot/grub/grub.cfg with your old one. I really think that *should* work! Take care, ks. Wojciech Kuzyszyn pgp2uRUfi6EGx.pgp Description: Podpis cyfrowy OpenPGP
