FYI I was using 4.10.0-26 for the past days before the 400+ packages upgrade in artful. I am using snapper to get periodic system snapshots (pre/post apt install|remove and also hourly/daily/weekly).
The actual behavior was that a short time after boot the btrfs cleaner/transaction process got permanently stuck to 100% in a single CPU. After that the system cycled between somewhat responsive to unresponsive every couple/few minutes. Unresponsiveness varied: - a terminal command was unresponsive and only finished later on - no screen refresh in a workspace, but I was able to cycle between workspaces - sometimes even X got unresponsive (not even a cursor) tl;dr I finally got it to work by disabling btrfs quotas on the root subvolume. I did enable it afterward and had no problems so far. For the sake of keeping some history on what I did in between, here are the steps I tried: 1) Waited for a couple hours in case btrfs was stuck due to too many snapshots. I am using snapper to get periodic system snapshots and I did notice that apt-get install/remove was getting slight slower in the past days under 4.10.0-26. 2) Waiting in step #1 didn't help, so I rebooted into 4.11.0-10, still the same issue. 3) I thought about rebooting into 4.10.0-26, but then I read one report about btrfs snapshots changes in the kernel causing the slowdown on netgear NAS devices and it was not possible to downgrade due to those changes. There was no information what kernel version was that and - since I had to browse from the phone - whether there were any such changes between 4.10 to 4.11 so I decided to avoid downgrading just in case. 4) Rebooted into 4.11.0-13 again, still the same issue - as expected. 5) I had around 40 snapshots between pre/post apt installs and hourly/daily/weekly snapshots from snapper, so I set a lower threshold and had snapper drop the oldest ones. Didn't help. 6) On the same netgear page I saw some users reporting that disabling btrfs quota helped (some said it didn't). Tried that on the root subvolume and it helped - I have various subvolumes, but it worked on the first try for root. I did enable quotas again to check if the btrfs cleaner/transaction was going to misbehave again, but everything is still running smooth. Didn't try rebooting yet - I will report back if rebooting turns out to be an issue. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1710653 Title: Reboot into linux 4.11.0-13 after update caused 100% cpu on btrfs- cleaner/btrfs-transaction To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1710653/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
