For Trusty and Xenial, fstrim is scheduled via cron[0] to run weekly at each Sunday at 6h47[1]. For Bionic onward, fstrim is scheduled via systemd timer to also run weekly[2]
Impacted users may want to take action before the next scheduled run by downgrading the running kernel or temporarily disabling the fstrim job. [Trusty and Xenial] By default, an /etc/cron.weekly/fstrim job is installed, but this may be supplanted by local modifications. Check if you are running a cron job which might invoke fstrim: $ sudo grep -r fstrim /etc/cron* If an fstrim job is found in the results of the above command, edit the appropriate file and comment out the command with a “#” at the beginning of the line to disable the execution of fstrim. For the default Ubuntu configuration, the command in the /etc/cron.weekly/fstrim file starts with “/sbin/fstrim” or “exec fstrim- all” and is the last line of the file. [Bionic or late] $ sudo systemctl disable --now fstrim.timer $ sudo systemctl mask fstrim.service [0] - /etc/cron.weekly/fstrim [1] - grep -i weekly /etc/crontab: [2] - systemctl status fstrim.timer | grep "Trigger:" -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1907262 Title: raid10: discard leads to corrupted file system Status in linux package in Ubuntu: Confirmed Status in linux source package in Trusty: Invalid Status in linux source package in Xenial: Invalid Status in linux source package in Bionic: Fix Committed Status in linux source package in Focal: Fix Committed Status in linux source package in Groovy: Fix Committed Bug description: Seems to be closely related to https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1896578 After updating the Ubuntu 18.04 kernel from 4.15.0-124 to 4.15.0-126 the fstrim command triggered by fstrim.timer causes a severe number of mismatches between two RAID10 component devices. This bug affects several machines in our company with different HW configurations (All using ECC RAM). Both, NVMe and SATA SSDs are affected. How to reproduce: - Create a RAID10 LVM and filesystem on two SSDs mdadm -C -v -l10 -n2 -N "lv-raid" -R /dev/md0 /dev/nvme0n1p2 /dev/nvme1n1p2 pvcreate -ff -y /dev/md0 vgcreate -f -y VolGroup /dev/md0 lvcreate -n root -L 100G -ay -y VolGroup mkfs.ext4 /dev/VolGroup/root mount /dev/VolGroup/root /mnt - Write some data, sync and delete it dd if=/dev/zero of=/mnt/data.raw bs=4K count=1M sync rm /mnt/data.raw - Check the RAID device echo check >/sys/block/md0/md/sync_action - After finishing (see /proc/mdstat), check the mismatch_cnt (should be 0): cat /sys/block/md0/md/mismatch_cnt - Trigger the bug fstrim /mnt - Re-Check the RAID device echo check >/sys/block/md0/md/sync_action - After finishing (see /proc/mdstat), check the mismatch_cnt (probably in the range of N*10000): cat /sys/block/md0/md/mismatch_cnt After investigating this issue on several machines it *seems* that the first drive does the trim correctly while the second one goes wild. At least the number and severity of errors found by a USB stick live session fsck.ext4 suggests this. To perform the single drive evaluation the RAID10 was started using a single drive at once: mdadm --assemble /dev/md127 /dev/nvme0n1p2 mdadm --run /dev/md127 fsck.ext4 -n -f /dev/VolGroup/root vgchange -a n /dev/VolGroup mdadm --stop /dev/md127 mdadm --assemble /dev/md127 /dev/nvme1n1p2 mdadm --run /dev/md127 fsck.ext4 -n -f /dev/VolGroup/root When starting these fscks without -n, on the first device it seems the directory structure is OK while on the second device there is only the lost+found folder left. Side-note: Another machine using HWE kernel 5.4.0-56 (after using -53 before) seems to have a quite similar issue. Unfortunately the risk/regression assessment in the aforementioned bug is not complete: the workaround only mitigates the issues during FS creation. This bug on the other hand is triggered by a weekly service (fstrim) causing severe file system corruption. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1907262/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
