25

After upgrading from Ubuntu 12.04 to Ubuntu 12.10, I get a message "scanning for btrfs file systems" at starting-up. I don't have any BTRFS filesystem. It delays the booting for about 15 seconds.

How can I get rid of this?

15

The btrfs-tools package adds an action to the initramfs to load the btrfs module. If you purge that package (sudo apt-get purge btrfs-tools), followed by an update-initramfs -ukall if the uninstallation doesn't do it already, that should go away (though I've not tested it). If it doesn't, you can always blacklist the brtfs module in /etc/modprobe.d.

  • 1
    Doing this on Ubuntu server 16.04 apt gives me "The following packages will be REMOVED: btrfs-tools* ubuntu-server*". Hmm, I'd like to keep the server though... – elomage Apr 29 '17 at 21:02
  • 1
    @elomage, ubuntu-server is just a meta-package that is used to pull packages typically found on server-style installations as dependencies. By removing it (provided no other package are removed as a result), you're not removing any software. – Stéphane Chazelas Apr 30 '17 at 7:55
  • Thanks. Improved my elementary Juno startup times. – Jürgen Hörmann Nov 16 '18 at 21:03
9

On Ubuntu 18.04 you can uninstall btrfs-support with

apt purge btrfs-progs

But that probably wouldn't save you much boot time. On my system the reason was, that I don't have a swap partition but on boot it is searched for such for about 30 seconds (while displaying the btrfs-scan).

You can remove the swap check with

  • open /etc/initramfs-tools/conf.d/resume
  • replace RESUME=UUID=xxx with RESUME=none
  • issue sudo update-initramfs -u
  • reboot your system

source: https://askubuntu.com/a/1034952/34298

4

Btrfs isn’t too much stable to be used as deafult file-system. Most Linux distributions, probable all, are still using ext4 as primary file-system. So, you can completely remove it from your computer. Try the given command:

sudo apt-get purge btrfs-tools

This command will remove btrfs-tools from your computer. You may need to wait some minutes to complete the process. Your initramfs should be updated automatically but if not happen, do it by this command:

sudo update-initramfs -ukall

Then make a grub update:

sudo update-grub

All is well. Now make a restart. Hope your Ubuntu will start successfully this time.

Reference: http://www.ugcoder.com/disable-scanning-for-btrfs-file-systems-in-ubuntu/

Let me know if you have some questions still.

  • The package is not installed on my system. So i tried echo "blacklist btrfs">>/etc/modprobe.d/blacklist.conf But no effect. still scanning for btrfs on boot – rubo77 May 9 '18 at 17:02
3

I saw this as well on 18.04 during boot. Since

/usr/share/initramfs-tools/scripts/local-premount/btrfs

calls for the scan, you can workaround this issue by dealing with that file. Since I wasn't using btrfs regularly, I purged the file through

sudo apt purge btrfs-progs
  • To get rid of that message, you need to do sudo update-initramfs -ukall as well. But still, that doesn't help much, the boot process then hangs at the step before saying Begin: Running /scripts/local-premount – rubo77 May 10 '18 at 6:36
1

It is the btrfs kernel module that does the scanning (for filesystems scanning multiple devices).

I have not found an indication that this is configurable, so your only options seems to be removing that module from your kernel (modprobe -r btrfs) assuming your kernel supports that.

  • 1
    I tried, but it seems like this has no effect on Ubuntu 18.04 – rubo77 May 9 '18 at 17:00
-1

The script which starts the search looks for the existence of btrfs. Simply renaming the executable /sbin/btrfs to p.e /sbin/btrfs.save (as sudo) will eliminate the search , gaining some 10-20 seconds in the boot-process!

  • 2
    it is not recommended to just delete system files. better uninstall the btrfs too with apt purge btrfs-tools – rubo77 May 10 '18 at 6:38

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