[Bug 1839219] [NEW] "minimum alignment" check has multiple issues

[Chris Graham]

Public bug reported:

I was installing to an external SSD, HP P600 to be specific.

This is an annoying bit of hardware, as it's actually 2 125GB SSDs in a
single case, so functions as 2 drives.

The message...

"The partition ... starts at an offset of 3584 bytes from the minimum
alignment for this disk, which may lead to very poor performance.

Since you are formatting this partition, you should correct this problem
now by realigning the partition, as it will be difficult to change
later. To do this, go back to the main partitioning menu, delete the
partition, and recreate it in the same position with the same settings.
This will cause the partition to start at a point best suited for this
disk"

There are 2 options "Go Back" and "Continue".

The issues...

1) Both buttons "Go Back", there is no way to ignore the error and
continue. So you need to either only have the "Go Back" button, or truly
allow the user to ignore the issue.

2) The advice is incorrect. Recreating the partition does not solve the
problem. The problem was with the default partition table on the
devices. I have no idea why it was like that, but the resolution was to
wipe the partition table, not just recreate the partition without the
existing table. This was not trivial to work out, I was messing around
trying to find what to do for a while.

** Affects: debian-installer (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1839219

Title:
  "minimum alignment" check has multiple issues

Status in debian-installer package in Ubuntu:
  New

Bug description:
  I was installing to an external SSD, HP P600 to be specific.

  This is an annoying bit of hardware, as it's actually 2 125GB SSDs in
  a single case, so functions as 2 drives.

  The message...

  "The partition ... starts at an offset of 3584 bytes from the minimum
  alignment for this disk, which may lead to very poor performance.

  Since you are formatting this partition, you should correct this
  problem now by realigning the partition, as it will be difficult to
  change later. To do this, go back to the main partitioning menu,
  delete the partition, and recreate it in the same position with the
  same settings. This will cause the partition to start at a point best
  suited for this disk"

  There are 2 options "Go Back" and "Continue".

  The issues...

  1) Both buttons "Go Back", there is no way to ignore the error and
  continue. So you need to either only have the "Go Back" button, or
  truly allow the user to ignore the issue.

  2) The advice is incorrect. Recreating the partition does not solve
  the problem. The problem was with the default partition table on the
  devices. I have no idea why it was like that, but the resolution was
  to wipe the partition table, not just recreate the partition without
  the existing table. This was not trivial to work out, I was messing
  around trying to find what to do for a while.

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