Slow installation mdadm RAID5
When installation your operating system on (primarily) large storage devices placed in RAID5 using mdadm, you might experience very slow installation speeds. This is due to the fact that most of the storage bandwidth is being used by the installer to initialize/synchronize the array. To allow the installation to finalize much sooner, we may limit the synchronization speed so the installer has much more bandwidth left to install the actual operating system.
This can be done via the following steps:
Press CTRL + ALT + F2 to enter a second terminal and press Enter to make it an active terminal.
Insert the following commands in this terminal:
echo 50000 > /proc/sys/dev/raid/speed_limit_max
echo 10 > /proc/sys/dev/raid/speed_limit_min
You may verify the synchronization speed has gone down significantly using the following command, looking at the 'speed' value
Returing to the installation screen can be done with the key combination CTRL + ALT + F1.