Scrub process interferes with loading and play the game and prevent shut down system

[VladimirMrzv]

On my system i use HDD drive with btrfs, volume is 12 Tb.
Every month is started scrub process but i not use pc 24x7 and when want shutdown or reboot system wait stopping process very long. For scrub I need more 20 hours and cannot ending this process. I think it is need continius process from last block not begin from first evry time.
Also I play games and one game become very long time to load and got staters when playing. All problem from scrub, after cancel all ok. but it starts again when playing.

My system Ubuntu 24.10 and btrfs-progs v6.6.3

[Forza-tng]

You can read about limiting scrub's performance imact on https://btrfs.readthedocs.io/en/latest/Scrub.html

You can cancel and resume scrubs too using btrfs scrub cancel and btrfs scrub resume.

https://btrfs.readthedocs.io/en/latest/btrfs-scrub.html

[adam900710]

And I believe it will be even better if we can add an option to btrfs scrub start to limit the speed (using the same sysfs interface).

As the sysfs interface is not really an end user friendly solution (one has to create a script doing all the wrapping and setting the sysfs interface instead).

[VladimirMrzv]

@Forza-tng thanks. Now i stop scrub before play game, but is starts again after some time.
After reboot it starts from beginning and not resume last.

[Forza-tng]

@Forza-tng thanks. Now i stop scrub before play game, but is starts again after some time. After reboot it starts from beginning and not resume last.

If it starts again it may be you have some maintenance service interfering.

[VladimirMrzv]

After boot PC, scrub process begins from start. Then cancel scrub and reboot system, after boot send command to resume and it continuous scrubbing, not start again from beginning. I think it must be automatic, trying resume and only then start.

[VladimirMrzv]

How I can stop scrub and run only manual?
If I cancel process, some time ago it starts again but not resume, it starts from beginning.

find config and change intervals, does it helps or not?

# cat /etc/btrfsd/settings.conf 
#
# Configuration for Btrfsd
#

# Settings can be adjusted per mountpoint,
# if no settings are defined for a mountpoint,
# the ones from the "default" section are used.
# Check man btrfsd(8) for more informtion.

[default]
# Address to send mails about filesystem errors to
mail_address=""

# Approximate intervals at which to execute
# maintenance actions.
stats_interval=10h
scrub_interval=3M
balance_interval=never

[VladimirMrzv]

yesterday finished scrub process, but need manual cancel before power off or reboot and resume after boot with option resume. I think need check start process and force resume not start