I am not able to extend the file system / root which is currently at 100% and I have tried to add a additional volume at os level

Even "vgdisplay" gives the error:

/etc/lvm/cache/.cache.tmp: write error failed: No space left on device

I am not able to find the any files that can be deleted to free up a little bit of space and also not able to extend due to the above error.

Also the mount / umount of a shared file system gives the error as the / root is at 100%

mount gives the error:

error writing /etc/mtab.tmp: No space left on device

umount gives the error:

umount: : device is busy. (In some cases useful info about processes that use the device is found by lsof(8) or fuser(1))

kindly please suggest here


  • It should be easy to free up a very limited amount of space - e.g. by temporarily moving man-pages to another disk. This should be plenty to allow growing your volume online without the need to reboot. Commented Apr 16, 2020 at 5:54

1 Answer 1


I would recommend rebooting the system into a Recovery mode where you will be able to grow your volume.

If rebooting is not feasible, you could try the following steps:

  1. ls -l /var/log — find a reasonably large (1/2GB) gzip-d log file(s) that you can temporarily relocate to a ramdisk
  2. mv /var/log/some_large_log_file.gz /dev/shm — move the log file into a ramdisk under /dev/shm
  3. grow your volume — should have enough space now
  4. restore log file from /dev/shm back into /var/log
  • thanks for your prompt response. its a production account with so many customer db tenants. if the normal reboot can help by any chance?
    – Rahul
    Commented Apr 16, 2020 at 5:40
  • what type of unix system is this?
    – rtx13
    Commented Apr 16, 2020 at 5:43
  • its a redhat 6.8 Linux version 2.6.32-696.6.3.el6.x86_64
    – Rahul
    Commented Apr 16, 2020 at 5:51
  • okay I'll add an alternative approach to my answer, stand by...
    – rtx13
    Commented Apr 16, 2020 at 5:53
  • ... what does df return?
    – rtx13
    Commented Apr 16, 2020 at 6:09

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