[dm-crypt] Alignment issue with 4K disk

Eugen Rogoza eugen.rogoza at gmx.de
Sun Jan 10 01:25:19 CET 2016


Hi,

> Reporter should paste output of "lsblk -t" with device activated to check what underlying
> device report alignment limits are violated in storage stack).

I am the reporter and the output of 'lsblk -t' with encrypted partition mounted is below. sda2 is the one that works fine, sdc4 is the one that throws alignment warnings.

root at nuc:~> 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
  └─zuluCrypt-1001-NAAN-sda2-4071757814         0   4096        0    4096     512    1           128 128    0B
sdb                                             0    512        0     512     512    0 noop      128 128    0B
├─sdb1                                          0    512        0     512     512    0 noop      128 128    0B
├─sdb2                                          0    512        0     512     512    0 noop      128 128    0B
├─sdb3                                          0    512        0     512     512    0 noop      128 128    0B
└─sdb4                                          0    512        0     512     512    0 noop      128 128    0B
sdc                                             0   4096 33553920    4096     512    1 cfq       128 128   32M
├─sdc1                                          0   4096 33553920    4096     512    1 cfq       128 128   32M
├─sdc2                                          0   4096 33553920    4096     512    1 cfq       128 128   32M
├─sdc3                                          0   4096 33553920    4096     512    1 cfq       128 128   32M
└─sdc4                                          0   4096 33553920    4096     512    1 cfq       128 128   32M
  └─zuluCrypt-1001-NAAN-sdc4-1790378342        -1   4096        0    4096     512    1           128 128    0B



> That is indeed true and further info including 'dmsetup table' will be 
> necessary to tell what is really going on.

Output below. Again, sdc4 is the problematic one.

root at nuc:~> dmsetup table
zuluCrypt-1001-NAAN-sdc4-1790378342: 0 11406264975 crypt aes-xts-plain64 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 256 8:36 256
zuluCrypt-1001-NAAN-sda2-4071757814: 0 1324371456 crypt aes-xts-plain64 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 256 8:2 256


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