[Users] SSD trim support over a LUKS layer

[Narcis Garcia]

Thank you for recommendation; it's in my plans.
I hope sometime LXC allows to manage simfs/dir disk quotas, same as
vzquota. This is a very important matter for scenarios I have.

In the meanwhile, I administrer many OpenVZ/6 hosts without upgrade
calendar in short, and not all decisions (and time dedication) depend on
me. This is the reason to still be polishing OpenVZ/6 with Devuan/1.


El 27/4/19 a les 16:25, CoolCold ha escrit:
> I believe to have fixes and backports like this in to legacy version of
> product will not happen, and you should consider upgrading. Personally,
> I've upgraded to lxc.. it's quite primitive comparing to ovz 6, but it's
> enough for my needs.
> 
> On Sat, Apr 27, 2019, 17:49 spameden <spameden at gmail.com
> <mailto:spameden at gmail.com>> wrote:
> 
>     Yes, it's an issue in kernel. 
> 
>     As dm-crypt/luks layer isn't passing TRIM to the underlying device.
> 
>     /boot is not encrypted that's why it works for you.
> 
>     сб, 27 апр. 2019 г. в 11:11, Narcis Garcia <informatica at actiu.net
>     <mailto:informatica at actiu.net>>:
> 
>         See in the case that /dev/sda1 (Directly mounted as Ext4 on
>         /boot) works with Trim/Discard.
>         It's the sda2_crypt (layer over sda2) that is not detected to be
>         trimmable. Devuan's stock kernel does.
> 
>         CentOS issue #6548 may not be this same bug; I've tested now
>         with CentOS 6.8 with a similar (but not same) result*:*
> 
>         $ lsb_release -d
>         Description:    CentOS release 6.8 (Final)
> 
>         $ uname -a
>         Linux localhost.localdomain 2.6.32-642.el6.x86_64 #1 SMP Tue May
>         10 17:27:01 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
> 
>         $ lsblk --discard /dev/sda
>         NAME                                                 DISC-ALN
>         DISC-GRAN DISC-MAX DISC-ZERO
>         sda                                                        
>         0      512B       2G         0
>         ├─sda1                                                     
>         0      512B       2G         0
>         └─sda2                                                     
>         0      512B       2G         0
>           └─luks-f691f48b-8556-487d-ac64-50daa99ed4c9 (dm-0)       
>         0      512B       2G         0
> 
>         $ cat /etc/crypttab
>         luks-f691f48b-8556-487d-ac64-50daa99ed4c9
>         UUID=f691f48b-8556-487d-ac64-50daa99ed4c9 none luks,discard
> 
>         $ mount | grep -e discard
>         /dev/mapper/luks-f691f48b-8556-487d-ac64-50daa99ed4c9 on / type
>         ext4 (rw,discard)
>         /dev/sda1 on /boot type ext4 (rw,discard)
> 
>         $ sudo fstrim /boot
>         # (same result as Devuan/1 and OpenVZ/6 kernel: success)
> 
>         $ sudo fstrim /
>         fstrim: /: FITRIM ioctl failed: Operation not supported
> 
> 
>         El 26/4/19 a les 21:36, spameden ha escrit:
>>         Hi.
>>
>>         I've asked this question years ago (in
>>         2013): https://lists.openvz.org/pipermail/users/2013-August/005250.html
>>
>>         Let me know if it helps, but this bug should have been fixed
>>         in CentOS and RHEL at
>>         least: https://bugs.centos.org/view.php?id=6548
>>
>>         Maybe OpenVZ maintainers didn't pick up this fix in the
>>         openvz6 legacy kernel?
>>
>>         Thanks.
>>
>>         ср, 10 апр. 2019 г. в 10:45, Narcis Garcia
>>         <informatica at actiu.net <mailto:informatica at actiu.net>>:
>>
>>             Does anybody know how can I solve this?
>>
>>             $ lsb_release -d
>>             Description:    Devuan GNU/Linux 1.0 (jessie)
>>
>>             $ uname -a
>>             Linux bell1 2.6.32-openvz-042stab134.8-amd64 #1 SMP Fri
>>             Dec 7 17:18:40
>>             MSK 2018 x86_64 GNU/Linux
>>
>>             $ lsblk --discard /dev/sda
>>             NAME           DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO
>>             sda                   0      512B       2G         0
>>             ├─sda1                0      512B       2G         0
>>             └─sda2                0      512B       2G         0
>>               └─sda2_crypt        0        0B       0B         0
>>
>>             $ cat /etc/crypttab
>>             sda2_crypt UUID=***** none luks,discard
>>
>>             $ mount | grep -e discard
>>             /dev/mapper/sda2_crypt on / type ext4
>>             (rw,noatime,errors=remount-ro,barrier=1,data=ordered,discard)
>>             /dev/sda1 on /boot type ext4
>>             (rw,relatime,barrier=1,data=ordered,discard)
>>
>>             $ sudo fstrim /
>>             fstrim: /: the discard operation is not supported
>>
>>             Thank you.
>>
>>
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