Bug 203887 - CGroup writeback is not supported by `xfs` filesystem leading to errors when using containers.
Summary: CGroup writeback is not supported by `xfs` filesystem leading to errors when ...
Status: NEW
Alias: None
Product: File System
Classification: Unclassified
Component: XFS (show other bugs)
Hardware: Intel Linux
: P1 normal
Assignee: FileSystem/XFS Default Virtual Assignee
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2019-06-13 14:13 UTC by axel.borja.login
Modified: 2020-05-11 23:30 UTC (History)
1 user (show)

See Also:
Kernel Version: 4.14
Subsystem:
Regression: No
Bisected commit-id:


Attachments

Description axel.borja.login 2019-06-13 14:13:08 UTC
I am currently working on a Kubernetes cluster, which uses docker.

This cluster allows me to launch jobs. For each job, I specify a memory request and a memory limit.

The memory limit will be used by Kubernetes to fill the `--memory` option of the docker run command when creating the container. If this container exceeds this limit it will be killed for OOM reason.

When writing on disk, pages will be written-back on the RAM before being written to the disk. To do this the system will evaluate how many pages could be written-back using the sysctl `vm.dirty_ratio` (20 % by default) and memory from the root cgroup.

In case of intensive IO operations, it leads some containers to OOM errors.

xfs should be able to writeback using cgroup.
Comment 1 axel.borja.login 2019-06-13 14:15:50 UTC
My nodes are running under RHEL with a kernel 4.14 and I encounter OOM errors when writing with xfs.

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