For some years I had problems when updating or installing a site with composer from my vagrant box. I didn't know why - but it took way to much time, to unzip the files and to write them to the harddisk from the shared folders. My host is Linux/ Ubuntu and the data partition was formatted as ext4.
During the last days I experimented with behat and docker for automated tests ... during this experiments I did two things, which may have accelerated the composer installs as well:
In the vagrant box (and the host system) I installed p7zip:
sudo apt-get install p7zip-full
And on the host system I altered /etc/fstab (appended barrier=0 as option to my data partition):
# Automount Daten
UUID=1f8b23fc-7b08-4324-XXXXXXXX /media/username/Daten ext4 defaults,barrier=0 0 2
I have no clue which change sped up the harddisk or heavy composer operations ... but I'm glad about this surprise and wanted to note it down!