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Re: USB3 3TB HDD boot

From: Bob Lemar
Subject: Re: USB3 3TB HDD boot
Date: Mon, 4 Mar 2013 20:27:41 +0400

Thank you for your replies.

Yes, it is definitely BIOS problems as it doesn't allow to boot from
external drive directly (via BIOS boot order settings). It doesn't
show this drive at <F10> boot menu even after soft reboot. So BIOS
doesn't provide access to GRUB like to any other drives or USB

And I suppose to think that it is not a bug, it is a feature. And
feature of external drive, not a BIOS. Vendors of spinning external
drive try to limit "uptime" of theirs HDD. External HDD could start as
soon as USB is powered but do not want to do it. It only starts when
OS tell it to start up (this commands are magic for me).


- External drive is logically 4K (not a 512e thing). It is not a problem yet.

- USB 3 is not a problem yet. The drive doesn't work with USB 2 just
the same way. So it is not "nativeness" BIOS-USB hub communication

- BIOS behavior is correct (it power up USB);

- external drive behavior is correct (it is powered but starts only on
demand and it is sleeping in many cases including PC start);

- GRUB behavior is correct (it boots from drives that BIOS told him
about; only OS can detect this device as mass storage because it was
designed that way).

- Ales, you were absolutely right with floppy for booting CD trick
example. While MB, HDD firmwares and bootloader have predictable and
correct behavior some users would like to have bootloader feature
(GRUB command) that wake up external HDDs and re-detect drives.


- Boot USB thumb and use kexec to boot external HDD.
I did: (1) clone linux to external drive; (2) correct fstab at
external; (3) boot into internal drive OS; (4) mount external HDD
which became visible; (5) kexec images and boot external drive. // I
am not sure that only external drive files were used at second boot --
need to do clear experiment with minimal os at internal device or
thumb flash. kboot and petitboot are possible solve this problem.

- It is good point to create feature request at BugTracker. I wish
GRUB has command to power up external USB HDD and do manual redetect.
But I don't know what is happening technically when OS do it. I guess
I should find out it to be more specific while filling bug.

On Tue, Feb 12, 2013 at 11:19 PM, Aleš Nesrsta <address@hidden> wrote:
> Hi Bob,
> it is probably not GRUB bug according to Your description - it looks to
> be BIOS problem.
> 1.
> Currently I have no idea about Your HW, but it looks like Your xHCI (USB
> 3.0 controller) is not "native" part of the PC handled by BIOS, i.e.
> BIOS cannot boot from any device connected to USB 3.0 port.
> Or, if You are able to boot some another USB 3.0 devices on the same USB
> 3.0 port, BIOS probably cannot handle such huge device (4K sectors and
>>2TB) - or has some another problem with Your new device.
> But, unfortunately, the final result is the same - BIOS cannot load GRUB
> and any other boot loader from Your new SEAGATE drive => You cannot boot
> anything directly from such device.
> There is no (easy) solution for such situation - it looks to be similar
> situation like e.g. if You want boot from CD on some very old machine
> where BIOS is able to boot only from floppy and it doesn't support
> booting from CD...
> Possibly You can use some additional small USB flash disc connected to
> USB port where it can be handled by BIOS. Install GRUB manually on this
> additional device together with copy of linux and initrd images from
> SEAGATE Expansion, properly modify grub.cfg and boot Linux kernel from
> it. I am afraid there is no better way. :-(
> 2.
> Maybe is better to use GRUB BugTracker for such things, this case looks
> more like bug report than developer's talk.. :-)
> BR,
> Ales
> Bob Lemar wrote:
>> Hi, guys
>> I got new SEAGATE Expansion USB 3.0 and want to boot linux from it.
>> I have successfully booted various linuxes before with different
>> loaders from USB thumb flashes. But I cannot do it with this external
>> drive.
>> There are three problems: USB3, 4K sectors and >2TB.
>> I try grub2 (fedora 17). Grub2 doesn't power on external USB drive.
>> The drive is spinning up only after some OS is starting to load after
>> grub2. So grub2 and BIOS don't see external HDD.
>> Can someone point me out:
>> 1. either how to turn on external USB3 driver while computer is in grub2?
>> 2. or how to load OS with kexec from external USB3 4K sector drive
>> (from OS which is located at internal HDD)?
>> --
>> Best regards, Bob
>> _______________________________________________
>> Grub-devel mailing list
>> address@hidden
> _______________________________________________
> Grub-devel mailing list
> address@hidden

Best regards, Bob

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