Gentoo Archives: gentoo-user

From: James <wireless@×××××××××××.com>
To: gentoo-user@l.g.o
Subject: [gentoo-user] MBR & GPT dual compliant format
Date: Fri, 22 Jul 2016 16:06:09
1 Hello,
3 I thought I'd post a new thread on this issue. My goals is to have a single
4 default partition scheme on a sata disk that allows me to use either
5 Bios(mbr) or EFI(gpt) systems on these drives. Also the goal is to keep the
6 partition scheme unchanged (boot;root;swap;'usr/local') but be able to set
7 up different file systems and distributed file systems on these drives to
8 facilitate testing a wide variety of cluster architectures. I'd sure
9 appreciate some 'thinking outside the box' ideas for these mostly 2T sata
10 drives. I intend to only use one bootloader (grub legacy) but that is
11 not a fixed limitation. /usr/local will be the only storage if one of these
12 drives is used for secondary or additional capacity, thus preserving the
13 partition scheme.
15 Here is the essences of what Neil posted before::
17 You can use gdisk and a GPT whetheryou are using BIO or EFI. The
18 difference is in your first partition. For EFI it must be type EF00 and
19 formatted with FAT. For BIOS booting you need to start the disk with
20 a small BIOS compatibility partition of type EF02. This is 1M here and you
21 don't format or use it, it just has to be there. And.
23 I'm not sure it can be done. BIOS needs an EF00 partition at the start.
24 EFI calls for an EF00 partition, which is recommended at the start but I
25 don't think it's compulsory that it is there. I have heard of people
26 using sda2 as the ESP where sda1 is a Windows rescue partition. So you
27 may get away with
29 p1 EF02 partition
30 p2 EF00 partition, formatted as FAT and mounted at /boot
31 root and swap partitions as you see fit.
33 You could try it and see, but I'm not sure it could be guaranteed to work
34 on all EFI hardware, although it should work on all BIOS hardware........
36 I'd use gdisk to set the partition type to get the partition table listing
37 to include :: (EF02, EF00)?
39 This doc seems to suggest there is a way to configure such disks [1], as do
40 other docs I have read, but do not give explicit examples just how to do this.
42 So is at [1]:
44 v/s_GPT_and_BIOS_v/s_UEFI
47 Now, I should use GPT (gdisk) and label and setup the disk complete with a
48 gpt labeled table, but preserve the MBR for legacy booting of most bios
49 based systems? If that is correct, then here is what the partition scheme
50 could look like, for a 2T drive::
52 Number Start (sector) End (sector) Size Code Name
53 1 2048 411647 200.0 MiB EFO2 FAT
54 2 411648 270747647 128.9 GiB 8200 Linux swap
55 3 270747648 1859022847 757.3 GiB 8300 Linux filesystem
56 4 1859022848 3907022847 976.6 GiB 8300 Linux filesystem
58 Maybe someone can edit this table and show me an example (no worries on
59 boundaries or sizes) and include a few sentences to explain and guide me
60 on this effort?
63 curiously,
64 James


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Re: [gentoo-user] MBR & GPT dual compliant format R0b0t1 <r030t1@×××××.com>