On Feb 6, 2014, at 12:39 AM, Dariusz J. Garbowski <thuforuk(a)yahoo.co.uk> wrote:
On 05/02/14 05:46 PM, Przemek Klosowski wrote:
> On 02/04/2014 06:18 PM, Chris Murphy wrote:
>> And then we can definitely justify making them bigger. 550MB, or even 1GB.
It's neutral to plus
>> for performance for either HDDs or SSDs (faux short stroked in the former, and
overprovisioned for
>> the latter). Does anyone know why the convention is to create the ESP as the
first partition?
> At times in the past there was a race between BIOS support for large disks and hard
disk size, and
> BIOS boot code could not reach the far sectors of the disk. This even leaked into
Linux sometimes,
Right but BIOS only ever expected to have to read LBA 0, so it stands to reason
someone's not testing whether it can jump beyond LBA 28-bit addressing if it's an
ancient BIOS implementation; or beyond the MBR 32-bit address limit.
But since the UEFI spec is predicated on LBA 48-bit addressing, I think my diplomatic
language would be "WTF vendor" if UEFI firmware face planted on an ESP at the
end of a 5TB drive. I should test it.
Oh hey, it works with whatever UEFI VirtualBox uses. This is the layout. Firmware finds
shim.efi way out well beyond 3TB, and GRUB is finding its grub.cfg way out there as well
and boots the system fine.
Disk /dev/sda: 10240000000 sectors, 4.8 TiB
[…]
Number Start (sector) End (sector) Size Code Name
1 10238871552 10239999966 551.0 MiB EF00 EFI System
2 2048 1026047 500.0 MiB 0700
3 1026048 10238871551 4.8 TiB 0700
It still happens: I just had a case of this on Dell R620 (Ivy Bridge
Xeon) with over 3TB disk space and RHEL 6.5... Grub couldn't reach it's files to
boot OS.
RHEL 6.5 uses ancient GRUB 0.97 so the problem could be with the boot loader, or the
firmware.
However, without having this computer physical present, how can you tell it uses UEFI and
not BIOS? I certainly can't. Dell's spec sheet for it says in part "From
bezel to BIOS to packaging" which seems like just a tagline, not a spec per se. But
then the support page explicitly refers to it as BIOS:
Dell Server BIOS PowerEdge R620 Version 2.1.3
http://www.dell.com/support/drivers/us/en/04/DriverDetails/Product/powere...
In general, finding out whether a system's firmware is BIOS or UEFI is not easy.
Either they don't say, as if it isn't a selling point, yet telling me it uses the,
e.g. Intel C600 chipset isn't too obscure. HP pretty much universally refers to the
UEFI firmware updates as BIOS updates. Idiotic.
Chris Murphy