Subject: bug#27884: parted reports the partition is not optimally aligned, even though it's 1MiB-aligned

From: Phil Susi <[email-masked]>
Date: Wed, 20 Sep 2017 08:55:40 -0400

On 7/30/2017 6:46 PM, Alicia Boya García wrote:
> Hi.
> 
> Is there any explanation to this GNU parted output?
> 
> GNU Parted 3.2
> Using /dev/sde
> Welcome to GNU Parted! Type 'help' to view a list of commands.
> (parted) unit B                                                          
> (parted) p                                                               
> Model: Seagate M3 Portable (scsi)
> Disk /dev/sde: 4000787029504B
> Sector size (logical/physical): 512B/4096B
> Partition Table: gpt
> Disk Flags:
> 
> Number  Start     End             Size            File system  Name  Flags
>  1      1048576B  4000786153471B  4000785104896B  ext4
> 
> (parted) align-check                                                     
> alignment type(min/opt)  [optimal]/minimal?                              
> Partition number? 1                                                      
> 1 not aligned
> 
> Why does it say it's not aligned? Both the the start and the end are
> 1MB-aligned (and therefore trivially 4096B-aligned and 512B-aligned), am
> I right?

Maybe your drive is advertising a different optimal alignment.  What
does /sys/block/sde/queue/optimal_io_size say?