Long USB drive unmounting after copying data to it

Wrong Copying Progress and Long Disk Unmounting on Ubuntu

After copying significant amount of data to a USB drive the data get cached and need to be physically flushed to the drive before unmounting. 

By default, Ubuntu uses 20% of RAM for file caches.

Solution

There are some tunable settings that influence how the Linux kernel deals with the file system cache. 

All of them are connected with dirty data (or dirty memory) - data that is written into the cache but not saved on disk.

• dirty_ratio - maximum percentage of dirty system memory
• dirty_bytes - the same as dirty_ratio but specified in bytes
• dirty_background_ratio - percentage of dirty system memory at which background writeback will start
• dirty_background_bytes - the same as dirty_background_ratio but specified in bytes

$ sudo bash -c 'echo $((64*1024*1024)) > /proc/sys/vm/dirty_background_bytes'
$ sudo bash -c 'echo $((128*1024*1024)) > /proc/sys/vm/dirty_bytes'

In this case, coping progress shows correct speed, and unmounting takes only several seconds. 

To save this setting after reboot it’s required to add such a line into /etc/sysctl.conf:

vm.dirty_background_bytes = 67108864

vm.dirty_bytes = 134217728

This option is applied to all disks - external and internal ones what can reduce system performance.

Garmin SubMusic (on Ubuntu 18.04)

1. Install dependencies
2. Install Nextcloud
3. Install Music
4. Install Ampache
5. Install Garmin SubMusic

Nextcloud

Reference guide

Nextcloud 19 dependencies:

• PHP >=7.2
• MySQL/MariaDB
• Nginx

Ampache dependencies:

• PHP >=7.2
• MySQL/MariaDB
• Nginx
• Composer

Gedit transparent background

Some gnome applications (usual ones: gedit, gnome-calculator) can suddenly get looking incorrect (transparent background, visual artifacts, etc).

The reason could be a change in:
- Settings => Region & Language => Manage Installed Languages => Keyboard input method system
- Language Support => Keyboard input method system

Solution:

- remove ~/.xinputrc
- reboot