Mailinglist Archive: opensuse-support (155 mails)

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Re: [opensuse-support] Trimming on encrypted partitions
On 10/03/2019 12.49, Oleksii Vilchanskyi wrote:
On 2/28/19 2:06 PM, Carlos E. R. wrote:
Check your mount options. If you use LVM or encryption, things change, too.

For example:

Isengard:~ # fstrim -av
/: 376 MiB (394194944 bytes) trimmed

/home doesn't appear, it is encrypted.


Thanks for that, turns out the trimming wasn't working for my encrypted
partitions under LVM when I decided to check it.

Which is because I forgot to add the option "allow_discards" to
/etc/crypttab, and I did not reboot the machine since I did.

discard is still not working on my home. I changed /etc/crypttab on the
28/2 and rebooted six days ago:

cr_home /dev/disk/by-id/ata-KINGSTON_...-part5 none
timeout=300,allow_discards

But the log says:

<3.4> 2019-03-04T00:21:10.823356+01:00 Isengard systemd-cryptsetup 596 -
- Encountered unknown /etc/crypttab option 'allow_discards', ignoring.

Looking on man, it says:

discard
Allow discard requests to be passed through the encrypted
block device. This improves performance on SSD storage but has security
implications.


So, wrong syntax. Changing again, and scheduling another reboot.



Googling, I see that "--allow-discards" is an option for "cryptsetup"
command. Some posts mention that "allow_discards" exist somewhere in the
documentation.

The confusion could come from commands like "dmsetup table --showkeys"
that show "allow_discards" if enabled.


--
Cheers / Saludos,

Carlos E. R.
(from 15.0 x86_64 at Telcontar)

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