I have a nearly full external HDD mounted under /mnt. This HDD is around 1TB in size. My primary hard drive is around 200GB. Because of the relatively large difference in size of the two, linux sees my whole system as being past 95% full point which violates the reserved space requirement of 5%. Naturally, this causes me to not be able to log in because I'm not allowed to use that space. (I've reduced the reserved space requirement to 1% for the time being so I can log in.).

My question: how can I fix this? I have only consumed 3% of my primary hard drive space meaning I have nearly 200GB of available space. It doesn't seem reasonable that I should be locked out due to insufficient space just because I have a nearly full external hard drive mounted. Is there a fix to this?

[edit to provide more detail upon request]

me@xxxx ~ $ mount
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
udev on /dev type devtmpfs (rw,nosuid,relatime,size=5065004k,nr_inodes=1266251,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,noexec,relatime,size=1023832k,mode=755)
/dev/sda1 on / type ext4 (rw,noatime,errors=remount-ro,data=ordered)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k)
tmpfs on /sys/fs/cgroup type tmpfs (rw,mode=755)
cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,release_agent=/lib/systemd/systemd-cgroups-agent,name=systemd)
pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)
cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)
cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (rw,nosuid,nodev,noexec,relatime,net_cls,net_prio)
cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpu,cpuacct)
cgroup on /sys/fs/cgroup/perf_event type cgroup (rw,nosuid,nodev,noexec,relatime,perf_event,release_agent=/run/cgmanager/agents/cgm-release-agent.perf_event)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset,clone_children)
cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)
cgroup on /sys/fs/cgroup/pids type cgroup (rw,nosuid,nodev,noexec,relatime,pids,release_agent=/run/cgmanager/agents/cgm-release-agent.pids)
cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)
cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,nosuid,nodev,noexec,relatime,hugetlb,release_agent=/run/cgmanager/agents/cgm-release-agent.hugetlb)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=37,pgrp=1,timeout=0,minproto=5,maxproto=5,direct)
debugfs on /sys/kernel/debug type debugfs (rw,relatime)
mqueue on /dev/mqueue type mqueue (rw,relatime)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime)
fusectl on /sys/fs/fuse/connections type fusectl (rw,relatime)
/dev/sda6 on /home type ext4 (rw,noatime,data=ordered)
/dev/sdb1 on /mnt/media_drive type ext3 (rw,noatime,data=ordered)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,relatime)
cgmfs on /run/cgmanager/fs type tmpfs (rw,relatime,size=100k,mode=755)
tmpfs on /run/user/122 type tmpfs (rw,nosuid,nodev,relatime,size=1023832k,mode=700,uid=122,gid=131)
tmpfs on /run/user/1000 type tmpfs (rw,nosuid,nodev,relatime,size=1023832k,mode=700,uid=1000,gid=1000)
gvfsd-fuse on /run/user/1000/gvfs type fuse.gvfsd-fuse (rw,nosuid,nodev,relatime,user_id=1000,group_id=1000)

me@xxxx ~ $ df
Filesystem     1K-blocks      Used Available Use% Mounted on
udev             5065004         0   5065004   0% /dev
tmpfs            1023832     35556    988276   4% /run
/dev/sda1       19091584  11288172   7591732  60% /
tmpfs            5119144    510692   4608452  10% /dev/shm
tmpfs               5120         4      5116   1% /run/lock
tmpfs            5119144         0   5119144   0% /sys/fs/cgroup
/dev/sda6      207550056   6631692 190352376   4% /home
/dev/sdb1      961301000 830560452  81902548  92% /mnt/media_drive
cgmfs                100         0       100   0% /run/cgmanager/fs
tmpfs            1023832         0   1023832   0% /run/user/122
tmpfs            1023832        20   1023812   1% /run/user/1000

For the df command which shows 60%, it was showing as 100% yesterday but I deleted a lot of stuff (emptied trash, etc.). It's important to note that it shouldn't be currently showing 60% either as the drive is closer to 3% full.

I got the following error when I would try to log on.

Your session only lasted less than 10 seconds. If you have not logged out yourself, this could mean that there is some installation problem or that you may be out of diskspace. Try logging in with one of the failsafe sessions to see if you can fix this problem. [ ] View details(~/.xsession-errors file)

I dropped to shell and ran df and noticed my system (/dev/sda1) was 100% full. I deleted my trash and some large files in my downloads directory. I also ran tune2fs to set my reserved space requirement to 1% to allow myself some space to log in graphically.

  • Use the external drive as intended, then consider the umount command when finished....
    – eyoung100
    Apr 13, 2017 at 4:31
  • Can you show the output of the mount and df commands? Apr 13, 2017 at 4:53

1 Answer 1


Generally, changing the percentage of reserved space on the filesystem in question will help get you back into your system:

tune2fs -m 1 <path to device node your filesystem rests on>

Generally, the full disk in question will be whichever your /var folder rests on, whether that's the same as your / mount or a mount of its own.

That said, your problem (as identified by information since removed from your answer, but alluded to in the comments below this answer) was that you filled your / partition, and that your external drive's state was irrelevant.

  • I already did this in order to log into the system but I would rather maintain that 5% reserved space but I want the 5% to only apply to my primary hard drive. Not a storage drive. I only keep media on that external drive.
    – dgunn
    Apr 13, 2017 at 11:15
  • I'm not aware of any default meachanism that considers filesystem fill in aggregate, instead on a per-filesystem basis. Please include the output of the mount and df commands in your question, so we can better see what's going on. Apr 13, 2017 at 11:17
  • Added to original post.
    – dgunn
    Apr 13, 2017 at 11:24
  • None of your filesystems are more than 92% full, meaning none have less than 8% available, which is far better than the default cutoff of 5%. What, precisely, is the error message you're getting, and how did you conclude you're getting it because your disks are full? Include answers in the original question, please. Apr 13, 2017 at 11:40
  • 2
    Your external drive has absolutely nothing to do with why your system "looked full". The problem was, your / filesystem did fill up to 100%. And given you deleted a bunch of stuff, it sounds like you fundamentally fixed your problem. If you're trying to avoid filling your / filesystem, you need to avoid putting so much data there; without further information on what you removed, it sounds like you could add 1TB to your / filesystem and eventually run into the same problem. Apr 13, 2017 at 11:58

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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