[dm-crypt] Re: Aligning entire LUKS/LVM/Ext4 filesystem stack to 4K sectors

I think the quickest way to find out is:

"lsblk -o name,phy-sec,log-sec"

Output like this shows it nicely:

[ monster % ~ ] lsblk -o name,phy-sec,log-sec                         
[  5:57PM ]
NAME                   PHY-SEC LOG-SEC
sda                        512     512
├─sda1                     512     512
└─sda2                     512     512
  ├─vg_monster-lv_home     512     512
  ├─vg_monster-lv_swap     512     512
  └─vg_monster-lv_root     512     512
sdb                        512     512
├─sdb1                     512     512
└─sdb2                     512     512

Obviously playing around with the output parameters gives you plenty
flexibility.

Cheers
Erwin

On Wed, 2021-03-24 at 20:53 +0100, Johnny Dahlberg wrote:
> 
> 
> On Fri, 19 Mar 2021 at 23:21, Carlos E. R.
> <[email protected]> wrote:
> > On 19/03/2021 22.39, Johnny Dahlberg wrote:
> > > On 19/03/2021, Carlos E. R. <[email protected]> wrote:
> > > > On 19/03/2021 21.24, Johnny Dahlberg wrote:
> > > > > On 19/03/2021, Maksim Fomin <> wrote:
> > > > > > > On Friday, 19 March 2021 г., 19:09, Johnny Dahlberg <>
> > > > > > > wrote:
> > > > 
> > > > ...
> > 
> > 
> > > > Related question:
> > > > 
> > > > How can one, on an exiting encrypted partition, find out what
> > > > size is
> > > > using each layer, and if they are aligned or not?
> > > > 
> > > > I am using encrypted partitions on SSD and I'm a bit worried.
> > > > 
> > > > 
> > > 
> > > Hello Carlos!
> > > 
> > > First you would check the physical sector size of your SSD. It is
> > > most
> > > likely 4096 bytes (4K). You can check this by doing:
> > > 
> > > cat /sys/block/(the parent device such as
> > > nvme0n1)/queue/physical_block_size
> > 
> > On the two machines I have running now, both have an nvme system
> > disk, 
> > but only one has the encrypted partition on it; both use 512:
> > 
> > cer@Telcontar:~> cat /sys/block/nvme0n1/queue/physical_block_size
> > 512
> > cer@Telcontar:~>
> > 
> > Isengard:~ # cat /sys/block/sda/queue/physical_block_size
> > 512
> > Isengard:~ #
> > 
> > Hum!
> > 
> 
> 
> Since January 2011, all manufacturers began using Advanced Format
> (4096 bytes): https://en.m.wikipedia.org/wiki/Advanced_Format#History
> 
> From what I can find online, your Samsung 970 Evo Plus uses 8K
> sectors physically.
> 
> > 
> > I think I'm good -  no worries :-)
> > 
> > Thanks! :-)
> > 
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