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On Sunday, 16 June 2019 18:00:12 BST Grant Taylor wrote: |
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> On 6/15/19 7:04 AM, Peter Humphrey wrote: |
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--->8 |
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> > My question is: how much of the bootctl-installed image is essential |
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> > for booting? In other words, if I install the ~amd64 kernel (5.1.9), |
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> > what effect will that have on booting the rescue system; and if |
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> > I install the amd64 kernel (4.19.44), what effect will it have on |
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> > booting the plasma system? |
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> |
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> I think it largely depends on where things are installed to. |
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> |
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> Do the different installs share a common /boot? Or do they have |
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> separate /boot partitions? |
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> |
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> I assume the other file systems are separate e.g. / (root), /home. |
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The two systems share a /boot partition but are otherwise separate: nothing is |
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common to the two systems. |
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> > In practice, I install the ~amd64 kernel and hope it doesn't affect |
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> > the rescue system too much; and it seems not to. Could I do better? |
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> |
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> I don't know if it's better or not, but here's what I'd do. |
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> |
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> · I'd put each OS on it's own drive (if at all possible). |
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> · I'd have a separate /boot and / (root) for each OS. |
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> · I'd configure UEFI boot menu entries for each OS. |
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The main drive is a 256GB NVMe, with no spare slots for a second. I do have a |
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couple of ordinary SSDs in RAID-1 for data, but they're not significant here. |
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I could have separate boot partitions, but I haven't found a need yet. I do |
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have separate UEFI boot entries. |
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My point is that they boot different versions of the kernel, and I wondered |
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what risk that involved, since the image installed in the UEFI space cannot be |
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the same in the two cases. Mick seems to have answered that. |
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> That way, the only thing that's common between the OSs is the hardware |
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> and the UEFI. They are separate from the time that UEFI boot menu onward. |
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> |
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> I recommend the separate drives so that you can use the OS on the other |
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> drive to deal with a drive hardware issue. |
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> |
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> I /might/ be compelled to try to leverage the two drives for some swap |
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> optimization. I'd probably have a minimal amount of swap on the same |
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> drive as the OS and more swap on the other drive. That way each OS has |
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> some swap in the event that the other drive fails, yet still has more |
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> swap if the other drive is happy. So you benefit from the 2nd drive |
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> without being completely dependent on it. |
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Ah, swap. I have a 2GB swap partition near the beginning of the drive, pri=8, |
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and a 16GB one near the end, pri=4. The latter is supposed to cope with huge |
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compilations like chromium. (I tried USE=jumbo-build recently but it ground to |
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a silent halt. I haven't spent time yet investigating why.) |
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To answer another point, I keep most of my user stuff in its own partition |
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mounted under ~/common. I've done that for many years, since the days before |
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I settled on a permanent distro. I didn't want, say, SuSE fighting with Gentoo |
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for rights to my data. Both backups and general flexibility benefit from this |
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arrangement. |
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-- |
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Regards, |
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Peter. |
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