Recently I built a 12 cards rig, it run into low disk space in a few minutes, I found that /var/log/kern.log was eating the free space quickly. I followed this post to resolve the issue:
https://askubuntu.com/questions/771899/pcie-bus-error-severity-corrected

steps:
1.open /etc/default/grub, I use vi, you can use other text editors.
2.replace GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" by GRUB_CMDLINE_LINUX_DEFAULT="quiet splash pci=nomsi", save and exit text editor.
3.sudo update-grub, sudo reboot

 
I hope it helps.