We have a Linux CentOS server. Our 1 partition "/dev/md3" is 100% used. That's why Mongo DB is not being connected. Can someone let me know how to solve this issue. I think mounting the partition is the solution? But I also have to make sure that Data should not be destroyed.

The space details are the following. "/dev/md3" is the full and "/dev/md4" has 900 GB Free. We need to increase the space in "/dev/md3". So our all services & Mongo DB should start working again.

Filesystem     1K-blocks     Used Available Use% Mounted on
devtmpfs        65844948        0  65844948   0% /dev
tmpfs           65888636        0  65888636   0% /dev/shm
tmpfs           65888636    10760  65877876   1% /run
tmpfs           65888636        0  65888636   0% /sys/fs/cgroup
/dev/md3        20026172 19997792         0 100% /
/dev/md2          498468    88837    379375  19% /boot
/dev/nvme0n1p1    522228     2660    519568   1% /boot/efi
/dev/md4       901136592   258420 855080032   1% /home
/dev/loop0        763700     1200    722872   1% /tmp
tmpfs           13177728        0  13177728   0% /run/user/0
Or is there any way to move Mongo DB to another partition with more space?
  • Can you add more details about those RAID devices? mdadm -D /dev/md3 for example. Do you use LVM? lvscan Commented Jan 1, 2020 at 19:26

2 Answers 2


A simple workaround without changing file systems structure would be to move some directories in a subtree of /home (e.g. /home/shared ) and then create a symlink to the original path. For example, assuming your database data is in /var/dbdir, you could move it this way:

$ sudo mkdir /home/share
$ sudo chmod 755 /home/share
$ sudo mv /var/dbdir /home/share
$ sudo ln -s /home/share/dbdir /var/dbdir

The correct answer is to expand the partition, but, as a short term solution you could try to free up some space by emptying large files.

To do this, use the true command redirection.

: > very_large_file.txt

Or, you can cat in /dev/null

cat /dev/null > very_large_file.txt

Hope this helps

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