Set coolbits value on Fedora Linux

You sometimes need to set the coolbits value to overclock your GPU on Linux

You’ll need to install nvidia-xconfig

sudo dnf install nvidia-xconfig

Then you can set the cool bits value with the following command. Change 24 to the appropriate cool bits value. Refer to the link below.

sudo nvidia-xconfig --cool-bits=28

It’ll create a new xorg config file. Reboot to take advantage of cool bits being enabled.

https://wiki.archlinux.org/title/NVIDIA/Tips_and_tricks#Enabling_overclocking

Snapper reverting changes on Fedora

List snapper BTRFS snapshots with

snapper list

If you are in recovery mode on Fedora, add –no-dbus right after the snapper command. e.g.

snapper --no-dbus list

You can use the diff command to list the changes that happened between snapshots.

snapper --no-dbus diff 108..109

And to undo a change or all the changes between a snapshot, do the following. Where 108..109 are all the changes you want to remove. So essentially going back to snapshot 108.

snapper --no-dbus -v undochange 108..109

https://documentation.suse.com/sles/11-SP4/html/SLES-all/cha-snapper.html

Installing Discord on Fedora 33

For some reason a lot of applications out there do not have a built RPM package. Fortunately, there are a bunch of applications built into snap, so we can install snap and then install Discord.

You can also use the copr repo. Visit the following link for instructions.

Install Snap Store

sudo dnf install snapd

https://snapcraft.io/docs/installing-snap-on-fedora

Install Discord

snap install discord

You may need to try signing out and back in or restarting your computer for the applications to show up in your application menu.

You can also manually run the application with

snap run discord

OLED Screen Brightness on Fedora 33

By default Linux and OLED displays don’t really want to play well together. icc-brightness is a handy utility that resolves the problem, but all the instructions I found online were for Ubuntu/Debian based distributions.

https://github.com/udifuchs/icc-brightness

Fortunately, after a few failed attempts to compile the program I was able to figure out which dependency was required.

[admin@local icc-brightness]$ sudo make
cc -W -Wall  icc-brightness-gen.c -l lcms2  -o icc-brightness-gen 
icc-brightness-gen.c:9:10: fatal error: lcms2.h: No such file or directory
    9 | #include <lcms2.h>
      |          ^~~~~~~~~
compilation terminated.
make: *** [Makefile:10: icc-brightness-gen] Error 1
admin@local icc-brightness]$

We are missing the lcms2-devel package. Not sure if the utils package is required, but installed it anyway.

sudo dnf install lcms2-utils lcms2-devel

With that installed we can now make and install icc-brightness

sudo make install

Reboot the laptop and it should automatically start icc-brightness in the background and the brightness controls should work

You can find more information for installing on Debian based systems at the following link.

How To Setup Samba/CIFS Share on Fedora Server

We are going to setup a Samba/CIFS share on Fedora Server that we will then access from Windows 10.

  1. Install Samba/CIFS server packages
  2. Create user to access share
  3. Configure SELinux and firewall
  4. Connect to erver from Windows

1. Install Samba/CIFS Fedora Server Packages

First we need to install the samba package.

sudo dnf install samba
Installing SMB on Fedora
Samba Dependencies

Next, lets enable the Samba service so it automatically starts when the server boots up.

systemctl enable smb nmb
systemctl start smb

nmb is a “NetBIOS name server that provides NetBIOS over IP naming service to clients”
https://www.samba.org/samba/docs/current/man-html/nmbd.8.html

2. Setup Samba/CIFS User

We now need a user to connect to the Samba share with. You can use the commands below to to create a new user.

pdbedit only configures a current Linux system user for Samba. You can skip creating a new Linux user, but only if there is one already created that you can use.

sudo useradd -m sambaUser
sudo passwd sambaUser
sudo pdbedit -a sambaUser

3. Configure Server SELinux and Firewall Permissions

Configure SELinux permissions with the following command.

sudo setsebool -P samba_enable_home_dirs on

You can also just disable SELinux. Although it is not necessarily recommended.
How To Enable/Disable SELinux

sudo setsebool -P samba_enable_home_dirs on
sudo firewall-cmd --add-service=samba --permanent
sudo firewall-cmd --reload

4. Test Samba/CIFS Share from Windows

You can now test to see if the share works. Open up Windows Explorer. Type in the IP address of the server and connect.

\\ip-address\sambaUser

It should prompt you for a login. Enter the user and password you set up.

Connecting to Fedora Samba/CIFS server

If it loads, then congratulations! You have successfully setup a Samba/CIFS Share on Fedora Server. Create new directories or files or whatever else you need.

Successfully Connected to Fedora Samba/CIFS Server

Check out the following links for more information about setting up Samba.

https://fedoramagazine.org/fedora-32-simple-local-file-sharing-with-samba/
https://jewelhuq.wordpress.com/2017/12/08/how-to-install-samba-server-in-fedora/

https://fedoramagazine.org/fedora-32-simple-local-file-sharing-with-samba/

Where is my software RAID?!

There are a few different ways to view RAID information on Fedora. Here are two commands that can help.

1. Print Mdadm config

You can copy and past the following command to print the mdadm configuration.

cat /etc/mdadm.conf

It should return something similar to the following.

$ cat /etc/mdadm.conf
# mdadm.conf written out by anacondaMAILADDR root
AUTO +imsm +1.x -all
ARRAY /dev/md/Boot level=raid0 num-devices=6 UUID=21ce258a:015d0dd4:90d5b80e:ab04b7f7
ARRAY /dev/md/Root level=raid0 num-devices=6 UUID=4be32ad0:f3aa77bd:139d749d:4a6aab60 

We see from the above output that we have two raid arrays. Both RAID 0 over 6 drives.

2. Print mdstats

You can show the mdstats by running

cat /proc/mdstat

Should get output similar to the following.

$ cat /proc/mdstat
 Personalities : [raid0]
 md126 : active raid0 sdc2[0] sdf2[5] sde2[4] sdd2[1] sda2[2] sdb2[3]
       5856552960 blocks super 1.2 512k chunks
 md127 : active raid0 sdc1[0] sdf1[5] sde1[4] sdd1[1] sdb1[3] sda1[2]
       3133440 blocks super 1.2 512k chunks
 unused devices: 

This shows us the RAID size. About 5TB on one and 3GB on the other. The 3GB is used for the boot partition.

Other Notes

Apparently there is a difference between “mdadm” and “dm-raid”
Mdadm is for managing and creating software raids, while dm-raid interacts if a device like a laptop has a “fake RAID”

https://superuser.com/questions/721795/how-fake-raid-communicates-with-operating-systemlinux/721796#721796
https://stackoverflow.com/questions/23164384/what-is-the-difference-between-dm-and-md-in-linux-kernel

For more information on managing RAID with Mdadm, you can refer here.