I tried to turn off TRIM ("discard") on my ext4 filesystem, but I did not succeed.

I tried to add nodiscard option into /etc/fstab, but I can still see this:

# tune2fs -l /dev/md2 | grep discard
Default mount options:    journal_data_writeback user_xattr acl discard

OS is GNU/Debian, and the disk is an SSD.

  • 2
    Why do you think modifying the fstab would change the default mount options that stored in the filesystem metadata? Changing the fstab options will only change the options used at mount time.
    – Zoredache
    Oct 20, 2014 at 21:06
  • Well, because I couldn't find any better ideas to try. I looked on the internet on ways to set the fs to "nodiscard" but I couldn't find anything.
    – Alex Flo
    Oct 21, 2014 at 6:10

1 Answer 1


the command to remove "discard" is this
tune2fs -o^discard /dev/md2

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