On Friday 26 Aug 2016 12:33:47 Mick wrote: > On Friday 26 Aug 2016 09:32:25 Peter Humphrey wrote: > > In my search for a suitable boot method, I'm trying Mike G's > > systemd-boot ebuild. I've installed it with no problem, and now I reach > > the heart-in-mouth stage of actually replacing gummiboot with it. But > > first, the backup, including dd of what used to be called the MBR (what > > is it now?). > > > > # parted -l > > Model: Unknown (unknown) > > Disk /dev/nvme0n1: 256GB > > Sector size (logical/physical): 512B/512B > > Partition Table: gpt > > Disk Flags: > > > > Number Start End Size File system Name Flags > > > > 1 1049kB 3146kB 2097kB uefi bios_grub > > 2 3146kB 144MB 141MB fat32 boot boot, esp > > 3 144MB 4504MB 4360MB linux-swap(v1) swap > > 4 4504MB 15.0GB 10.5GB ext4 rescuesys > > 5 15.0GB 32.2GB 17.2GB ext4 gentoo > > 6 32.2GB 36.5GB 4295MB ext4 var > > 7 36.5GB 45.1GB 8590MB ext4 home > > > > [...] > > > > That start block of the uefi partition looks odd to me. > > The 'Name' of the 1st partition is the label you have provided when you > created it. It is NOT the type of the partition, which is shown under the > 'Flags' column as 'bios_grub'.
Yes, I know that of course. I called the first partition "uefi" because that's what the wiki used, and nothing more suitable suggested itself. > The 1st partition was created to accommodate Grub's boot code. Now that I didn't know. Well, I was hazy about it anyway. > It starts on the first cylinder (change the units in parted to cyl and > you'll see it starts at '0 cyl') and has no fs on it. Indeed, except that parted doesn't want to use cylinders in its list output. > > I'm pretty sure I didn't specify a start position to parted when I was > > constructing the partition layout six months ago, preferring to let the > > program choose a value itself. > > Parted and friends will create this partition for Grub at the very start > of the disk, when you use GPT. Quite so. > > I do remember, though, that parted had a strange idea of what > > 2MB meant: it's turned out to be 2097kB. > > You are mixing decimal and binary. 2MiB = 2 x 1024^2 = 2,097,152 Well, it isn't me who's mixing them, but parted. I was operating in MiB throughout, as far as I could tell. > > My question for the panel is whether I need to do anything about that > > partition layout. What do you think? > > You don't have to do something about it, if you want to retain the ability > to use Grub. If you will no longer use grub then you probably do not > need the first grub-specific partition. I hope I never have to look at grub-2 again. All the same, 2MiB is a small enough price to pay for flexibility. > As shown above the second partition is your EFI partition. 141MB may not > be enough to store many kernel images, but it depends on how many kernel > images and initramfs you keep in there at any time. I expect to hold two or three kernels in the boot partition: the latest, a recent known-working one and perhaps a long-term one. I haven't needed an initramfs yet. -- Rgds Peter
