Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm following the Arch Linux install instructions found here from a live cd, and I'm stuck issuing the following command:

# arch-chroot /mnt
mount: sys is already mounted or /mnt/sys busy
       sys is already mounted on /sys
       sys is already mounted on /mnt/sys
==> ERROR: failed to setup API filesystems in chroot /mnt

Can someone explain to me what sys is and how it got mounted? How do I proceed to install Arch from here? I tried to reload the live cd a number of times but I keep coming back to this.

share|improve this question
Would you mind indicating what partitions did you create exactly how you mounted and in what order? also, try with the latest iso (2013.01.04) – Martín Canaval Jan 15 '13 at 9:40
/mnt should not be used unless it is not used for mounting other filesystems (which is is, usually). Make a new folder somewhere such as /newChroot or /mnt/fresh-install, mount a block device there (/dev/sda1 for example) and use that as the root folder. – Ярослав Рахматуллин Mar 5 '13 at 7:44

/sys is a virtual file system that interfaces with the kernel. It is meant to replace /proc. More at

By the sounds of it, you have /mnt/sys mounted, try umount /mnt/sys or better yet, reboot. If it is doing this after the reboot, then arch-chroot is probably has a typo, mount /sys /mnt/sys should be mount --bind /mnt/sys. I could potentially help more if you could post the output of mount. Not sure if you have figured the solution out, as you posted it nearly a month ago.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.