[pkg-cryptsetup-devel] Bug#1016474: cryptsetup: The system installed on encrypted LVM (both root and swap partitions) freezes during massive writes

[Wojciech Zabołotny]

W dniu 01.08.2022 o 14:00, Guilhem Moulin pisze:

> On Mon, 01 Aug 2022 at 13:31:10 +0200, Wojciech Zabołotny wrote:
>> It may be related to incorrect assignment of priorities to kernel
>> threads responsible for encryption and swapping.
>>
>> The problem is also not new:
>> https://superuser.com/questions/1666684/debian-testing-linux-on-an-encrypted-lvm-filesystem-intensive-operations-cause
>>
>> Then it seemed that it is related to lack of entropy
> No, I/O on mapped dm-crypt devices doesn't drain the entropy pool.
>  
>> Well, maybe I should try recipes given here:
>> https://askubuntu.com/questions/1406444/what-is-causing-my-system-to-stall-freeze-corrupt-data-when-using-lvm-luks
>> and here: https://blog.cloudflare.com/speeding-up-linux-disk-encryption/
> Nothing here is related to the cryptsetup binary or other programs in
> src:cryptsetup.  These are only responsible for setting up the volume
> (formatting and mapping), I/O is done through the dm-crypt subsystem
> which is part of the kernel not src:cryptsetup.  Performance issues
> might point at slow ciphers, misalignment, or even dm-crypt, but not
> src:cryptsetup itself.
>
Hi,

Modifying the mapping parameters with:
 # cryptsetup  --perf-no_write_workqueue refresh name_of_the_mapping

indeed eliminates the problem.
Isn't it then the problem with default mapping parameters used in
cryptsetup?

With best regards,
Wojtek