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Re: 512e vs 4K sector confusion

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Hi,

Andy Smith wrote:
> what I meant was that fdisk showed a single partition of
> 3.2TB size, while the entire disk being only the 400G

Then it's what i would expect from fdisk.


> I did try using fdisk on the destination to delete the partition and
> recreate it with the correct numbers, but the ext4 driver and fsck
> and other filesystem tools were still totally unable to work with
> it. Yet, a sha256sum of the disk image file at both sides showed the
> same value, so it is the same data.

I would also expect complaints about read attempts after the end of
the device.


> Is it actually possible to create an LVM volume that thinks it has 512b
> logical sectors, on an underlying device that is 4Kn?

Interesting question.
Googling for LVM instructions ... pvcreate(8), vgcreate(8), lvcreate(8).
Their man pages show no options for selecting block sizes.

losetup(8) has an option which looks helpful:
  -b, --sector-size size
     Set the logical sector size of the loop device in bytes (since Linux
     4.14).
But that would be another software layer between filesystem and physical
device.
(losetup -b 4096 would possibly help to mount an image file from a disk
with logical block size 4K.)


Have a nice day :)

Thomas

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Thread

512e vs 4K sector confusion Andy Smith <andy@strugglers.net> - 2024-01-14 09:10 +0100
  Re: 512e vs 4K sector confusion Andy Smith <andy@strugglers.net> - 2024-01-14 09:20 +0100
    Re: 512e vs 4K sector confusion "Alexander V. Makartsev" <avbetev@gmail.com> - 2024-01-14 12:30 +0100
    Re: 512e vs 4K sector confusion Arno Lehmann <al@its-lehmann.de> - 2024-01-14 12:40 +0100
  Re: 512e vs 4K sector confusion "Thomas Schmitt" <scdbackup@gmx.net> - 2024-01-14 14:30 +0100
    Re: 512e vs 4K sector confusion Andy Smith <andy@strugglers.net> - 2024-01-14 17:20 +0100
      Re: 512e vs 4K sector confusion "Thomas Schmitt" <scdbackup@gmx.net> - 2024-01-14 18:00 +0100
  Re: 512e vs 4K sector confusion Timothy M Butterworth <timothy.m.butterworth@gmail.com> - 2024-01-14 19:20 +0100
  Re: 512e vs 4K sector confusion Stefan Monnier <monnier@iro.umontreal.ca> - 2024-01-15 05:40 +0100
    Re: 512e vs 4K sector confusion Andy Smith <andy@strugglers.net> - 2024-01-15 06:40 +0100
      Re: 512e vs 4K sector confusion Nicolas George <george@nsup.org> - 2024-01-15 22:30 +0100
      Re: 512e vs 4K sector confusion Nicholas Geovanis <nickgeovanis@gmail.com> - 2024-01-15 22:30 +0100
        Re: 512e vs 4K sector confusion Andy Smith <andy@strugglers.net> - 2024-01-16 01:40 +0100
        Re: 512e vs 4K sector confusion Teemu Likonen <tlikonen@iki.fi> - 2024-01-16 17:40 +0100
      Re: 512e vs 4K sector confusion Andy Smith <andy@strugglers.net> - 2024-01-17 08:30 +0100
  Re: 512e vs 4K sector confusion Andy Smith <andy@strugglers.net> - 2024-01-20 22:30 +0100

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