Re: kernel: device-mapper: table: 254:1: adding target device sda1 caused an alignment inconsistency
On Sat 28 Jul 2018 at 10:57:45 (-0300), Henrique de Moraes Holschuh wrote:
> On Sat, 28 Jul 2018, Rick Thomas wrote:
> > > rbthomas@small:~$ lsblk -t
> > > NAME ALIGNMENT MIN-IO OPT-IO PHY-SEC LOG-SEC ROTA SCHED RQ-SIZE RA WSAME
> > > sda 0 4096 33553920 4096 512 1 mq-deadline 60 128 0B
> > > `-sda1 0 4096 33553920 4096 512 1 mq-deadline 60 128 0B
> > > |-small-swap -1 4096 0 4096 512 1 128 128 32M
> > > |-small-root -1 4096 0 4096 512 1 128 128 32M
> > > `-small-home -1 4096 0 4096 512 1 128 128 32M
> > > mmcblk2 0 512 0 512 512 0 mq-deadline 128 128 0B
> > > |-mmcblk2p1 0 512 0 512 512 0 mq-deadline 128 128 0B
> > > `-mmcblk2p2 0 512 0 512 512 0 mq-deadline 128 128 0B
> > > rbthomas@small:~$
> >
> > Note the alignment values of “-1” for the lvm entries but not for the GPT partition or the whole disk.
> > Why do you suppose that is?
>
> Keep in mind that you *offset*-align the outer container *only*, and then inside
> you just keep the size alignment.
>
> So, the above ensures correct use of the partitions even if sda1 is
> unaligned.
>
> If you offset-align sda1 to -1, everything inside it should have an offset of
> zero to keep the alignment correct.
I don't think I fully understand the explanation. Can you point out
the number(s) that's wrong, and how it should be corrected.
(To which number does the -1 apply, and what units is it in?)
Below, sda is internal, sdb is USB-connected. The latter causes a pair
of messages when sdb2 is unlocked:
device-mapper: table: 254:1: adding target device sdb2 caused an alignment inconsistency:
physical_block_size=4096, logical_block_size=512, alignment_offset=0, start=33553920
device-mapper: table: 254:1: adding target device sdb2 caused an alignment inconsistency:
physical_block_size=4096, logical_block_size=512, alignment_offset=0, start=33553920
What is it that "starts" at 33553920?
$ lsblk -t
NAME ALIGNMENT MIN-IO OPT-IO PHY-SEC LOG-SEC ROTA SCHED RQ-SIZE RA WSAME
sda 0 4096 0 4096 512 1 cfq 128 128 0B
├─sda1 0 4096 0 4096 512 1 cfq 128 128 0B
├─sda2 0 4096 0 4096 512 1 cfq 128 128 0B
├─sda3 0 4096 0 4096 512 1 cfq 128 128 0B
├─sda4 0 4096 0 4096 512 1 cfq 128 128 0B
├─sda5 0 4096 0 4096 512 1 cfq 128 128 0B
├─sda6 0 4096 0 4096 512 1 cfq 128 128 0B
├─sda7 0 4096 0 4096 512 1 cfq 128 128 0B
├─sda8 0 4096 0 4096 512 1 cfq 128 128 0B
│ └─swanhome 0 4096 0 4096 512 1 128 128 0B
├─sda9 0 4096 0 4096 512 1 cfq 128 128 0B
├─sda10 0 4096 0 4096 512 1 cfq 128 128 0B
├─sda11 0 4096 0 4096 512 1 cfq 128 128 0B
├─sda12 0 4096 0 4096 512 1 cfq 128 128 0B
├─sda13 0 4096 0 4096 512 1 cfq 128 128 0B
└─sda14 0 4096 0 4096 512 1 cfq 128 128 0B
sdb 0 4096 33553920 4096 512 1 cfq 128 128 32M
├─sdb1 0 4096 33553920 4096 512 1 cfq 128 128 32M
└─sdb2 0 4096 33553920 4096 512 1 cfq 128 128 32M
└─luks-0229da67-… -1 4096 0 4096 512 1 128 128 0B
$
Here's the partitioning of these disks:
$ sudo gdisk -l /dev/sda
GPT fdisk (gdisk) version 1.0.1
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
Disk /dev/sda: 976773168 sectors, 465.8 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 2653F13F-2CD0-406F-B004-6AFFDBE18127
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 976773134
Partitions will be aligned on 2048-sector boundaries
Total free space is 4077 sectors (2.0 MiB)
Number Start (sector) End (sector) Size Code Name
1 2048 2050047 1000.0 MiB 2700 Basic data partition
2 2050048 2582527 260.0 MiB EF00 EFI system partition
3 2582528 4630527 1000.0 MiB ED01 Basic data partition
4 4630528 4892671 128.0 MiB 0C01 Microsoft reserved ...
5 4892672 347348991 163.3 GiB 0700 Basic data partition
6 347348992 429268991 39.1 GiB 8300 Linux-A
7 429268992 511188991 39.1 GiB 8300 Linux-B
8 511188992 883275775 177.4 GiB 8300 Linux-Home
9 883275776 883292159 8.0 MiB EF02 Linux-BIOS-Boot
10 883292160 892084223 4.2 GiB 8200 Linux-Swap
11 892086272 892803071 350.0 MiB 2700
12 892803072 894900223 1024.0 MiB 0700 Basic data partition
13 894900224 947329023 25.0 GiB 0700 Basic data partition
14 947329024 976773119 14.0 GiB 2700 Basic data partition
$
$ sudo fdisk -l /dev/sdb
Disk /dev/sdb: 931.5 GiB, 1000204885504 bytes, 1953525167 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 33553920 bytes
Disklabel type: dos
Disk identifier: 0x6bc6bcdc
Device Boot Start End Sectors Size Id Type
/dev/sdb1 2048 1302349823 1302347776 621G 7 HPFS/NTFS/exFAT
/dev/sdb2 1302349824 1953521663 651171840 310.5G c W95 FAT32 (LBA)
$
In case it helps:
# cryptsetup luksFormat /dev/sdb2
[…]
# cryptsetup open --type luks /dev/sdb2 thequiz
Enter passphrase for /dev/sdb2:
# mkdosfs -v -i 20141210 -F 32 -n quiz02 /dev/mapper/thequiz
mkfs.fat 4.1 (2017-01-24)
mkfs.fat: warning - lowercase labels might not work properly with DOS
or Windows
/dev/mapper/thequiz has 255 heads and 63 sectors per track,
hidden sectors 0x0000;
logical sector size is 512,
using 0xf8 media descriptor, with 651106305 sectors;
drive number 0x80;
filesystem has 2 32-bit FATs and 64 sectors per cluster.
FAT size is 79488 sectors, and provides 10171051 clusters.
There are 64 reserved sectors.
Volume ID is 20141210, volume label quiz02 .
# cryptsetup luksClose thequiz
#
Cheers,
David.
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