Re: GRUB2 not able to read ext4/xfs file systems on 8 TB drive

[Pascal Hambourg]

Hello,

Le 20/04/2020 à 04:01, Niklas Hambüchen a écrit :
> I'm writing to report that my GRUB2 (2.02 and 2.04) seems to have issues to 
> correctly read the single ext4 and XFS file systems with ~8 TB of size on an 8 
> TB hard drive.
>
> It incorrectly shows some empty directories.
>
> Details:
>
> * Server: HP DL120 G7, 32 GB RAM hosted by Leaseweb
> * Hard drives: 2x TOSHIBA MG05ACA8, firmware GX2A
> * Partitioning scheme:
>    * GPT partitions -> mdadm RAID1 -> LVM -> ext4
>    * 1 MB BIOS boot partitions (sda1,sdb1), the RAID1 is over (sda2,sdb2)
>    * mdadm metadata 1.2 (the current default)
(...)
> When I do not make an 8 TB ext4/xfs file system, but use a small ext2 /boot 
> partition, then GRUB2 works fine.
>
> What is going on here?
>
> Should GRUB2 be able to read from a single 8 TB ext4/xfs file system? Is this a 
> bug?

By default GRUB uses firmware disk drivers which rely on the platform 
firmware (BIOS or UEFI) to access drives. Is the firmware able to 
address 8 TB capacity ? It has been reported that some BIOS firmwares 
cannot read sectors beyond 2 TiB.

You may test by switching from firmware disk drivers to GRUB native disk 
drivers with the "nativedisks" commands. Be aware that drive names 
change and (hdX) are not available any more, so any needed module must 
be loaded first.