Questions tagged [sysfs]
12 questions
54
votes
7 answers
How do I modify "/sys/kernel/mm/transparent_hugepage/enabled"
I use mongodb 3.0 and I find a warning: MongoDB shell version: 3.0.0 connecting to: test Server has startup warnings: 2015-03-13T16:28:29.405+0800 I CONTROL [initandlisten] 2015-03-13T16:28:29.406+0800 I CONTROL [initandlisten] ** WARNING:…
Feng Yu
- 857
- 3
- 8
- 18
32
votes
1 answer
What's the "/sys" directory for?
A while ago I noticed this directory that I had not ever seen before, /sys . I researched a bit and read that "modern Linux systems" often have this directory, and that it manages devices. I thought that was what /dev was for. I can't seem to find a…
Chev_603
- 1,728
4
votes
2 answers
No `rc.local` in 16.10, so how can I add a command to set brightness on boot?
I previously solved the problem by adding a command: echo X > /sys/class/backlight/intel_backlight/brightness to /etc/rc.local on Ubuntu 14.04 . But there is no /etc/rc.local on Ubuntu 16.10 . I don't know how to solve it now. Is there a new script…
Ims Joe
- 43
3
votes
2 answers
'cat': can't open file: Permission denied
I am trying to copy the whole / directory to some other location. When doing cp recursively, it fails on some files like:- / # ls -lrt /sys/module/nf_conntrack_ipv4/uevent --w------- 1 root root 4096 Mar 7 06:29 /sys/module/nf_conntrack_ipv4/uevent…
Rahul
- 279
2
votes
1 answer
Ubuntu 16.04 Complicated Interface Names
I'm trying to figure out how to restore the simple interface names in Ubuntu 16.04. I.e. enp3s0 renamed to eth0 . I have tried to modify the GRUB configuration. I have tried editing /etc/udev/rules.d/10-network.rules , but both methods did nothing…
Faith Skater
- 63
2
votes
2 answers
how do I make "/sys/kernel/mm/transparent_hugepage/defrag" never status to close the THP warning
reboot the linux (ubuntu 16.04 redis 4.011) /var/log/redis.log shows # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo…
robspin
- 133
1
vote
1 answer
How to change permission for Sysfs file using udev rules
I am writing a custom module kernel that boots at startup. I can write in the sysFS file using this : echo -e "(0,0,255,750)\n" | sudo tee /sys/fs/led_sysfs/led_value But I will have another software that will need to write to the sysFs file. This…
Tamanar
- 11
0
votes
2 answers
How to delete debug files in /sys/kernel/debug?
sudo find / -size +5G -ls listed debug files with more than 8GB size at /sys/kernel/debug/dri/n/amdgpu_vram (n is the number of GPUs) These might be useless debug files. Cannot delete them (error "Operation not permited"). How to delete these files?
cjclm7
- 305
0
votes
0 answers
When running the dvb-fe-tool --femon command, a large number of error logs are recorded in the syslog
Every time I run the command dvb-fe-tool --femon, the following error logs are recorded in the syslog. Since the CPU load is also high, I would like to reduce it. If you know of any methods, please let me know. PRETTY_NAME="Ubuntu 24.04.1 LTS"…
tagawa
- 1
0
votes
1 answer
What is the point of creating a symlink in /dev direcory?
I understand that you can write custom udev rules to create a symlink in /dev directory. Wondering what having a symlink in /dev accomplishes? What is the symlink linking to? ACTION=="add", SUBSYSTEM=="usb", ATTRS{idVendor}=="0461",…
Dr. Chocolate
- 111
0
votes
0 answers
/etc setting to ping as non-root freely
Since some not long time ping stopped working as non-root (I'm not sure if it distro-wide or maybe it is my custom kernel). The ping is fixed by this command: sysctl -w net.ipv4.ping_group_range="0 1000" But the problem is I cannot add it to…
midenok
- 858
0
votes
1 answer
16.04 How do I stop Mongo 3.x.x and 4.x.x from complaining about WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'?
A default installation of MongoDB on Ubuntu 18.04 gives the following warning about transparent hugepage defrag. How to deal with it?
init0
- 101