Re: kernel: device-mapper: table: 254:1: adding target device sda1 caused an alignment inconsistency

[Rick Thomas <rbthomas@pobox.com>]

On Jul 27, 2018, at 8:19 PM, David Wright <deblis@lionunicorn.co.uk> wrote:

> On Fri 27 Jul 2018 at 18:46:02 (-0700), Rick Thomas wrote:
>> When booting, I get 12 error messages similar to the following (three groups of four, each group with a different “start” value and corresponding minor device)
>> 
>>> Jul 24 03:40:08 small kernel: device-mapper: table: 254:1: adding target device sda1 caused an alignment inconsistency: physical_block_size=4096, logical_block_size=512, alignment_offset=0, start=33553920
>> 
>> Can anyone tell me what it means and what I should do about it?
> 
> That's the same message as I reported on an MBR disk in
> https://lists.debian.org/debian-user/2018/02/msg00466.html
> 
> The post gives full details of the partitioning and the
> creation of the encrypted filesystem which precede getting
> the messages (in pairs).
> 
> There were no follow-ups.

Googling the contents of the subject line of this post gives:

    https://unix.stackexchange.com/questions/340484/device-mapper-table-alignment-inconsistency

which is slightly helpful.

Something else that is interesting is the following from “man pvcreate”:

> If a device is a 4KiB sector drive that compensates for windows partitioning (sector 7 is the lowest aligned  logical
>        block,  the  4KiB sectors start at LBA -1, and consequently sector 63 is aligned on a 4KiB boundary) manually account
>        for this when initializing for use by LVM.
>        pvcreate --dataalignmentoffset 7s /dev/sdb

Is it possible that I have such a device?

Enjoy!
Rick