btrfs-cleaner high CPU utilization and severe performance issues
This document (000020696) is provided subject to the disclaimer at the end of this document.
SUSE Linux Enterprise Server 12 Service Pack 3 and later
Looking at 'top' output shows btrfs-cleaner using very high percentage of CPU cycles.
There may be evidence of hangs in btrfs_qgroup_rescan_worker threads reported in messages log.
Trying to manipulate files on one or more btrfs filesystems may hang or takes a long time to complete (e.g. renaming a file).
# btrfs quota disable <filesystem>
e.g. to disable quotas on the root filesystem:
# btrfs quota disable /
To verify quota is disabled for a given filesystem, use:
# btrfs qgroup show <filesystem>e.g.
# btrfs qgroup show / ERROR: can't list qgroups: quotas not enabled
Where quotas are required and can not be disabled, customers with an appropriate SUSE support entitlement may open a support request in order to receive engineering test code which should address the problem.
This means, if the subvolume being deleted is not a snapshot, it will not cause any problems. If the subvolume has undergone a large amount of changes but has almost no shared subtree with the original one, again there will be no problem. If the subvolume itself is small, then still no problem.
This problem is being discussed in an upstream thread with a view to creating a solution to the problem.
This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.
- Document ID:000020696
- Creation Date: 15-Jul-2022
- Modified Date:15-Jul-2022
- SUSE Linux Enterprise Server
For questions or concerns with the SUSE Knowledgebase please contact: tidfeedback[at]suse.com