Disk Space
show space (linux)
In most operating systems, once you run out of space, the system will crash. When you get close to running out of space, other errors will start happening. Some tasks are smart enough to check for disk space before starting and if there isnt enough, the command will fail, sometimes silently. You can view disk space in linux using the df -h command:
Filesystem Size Used Avail Use% Mounted on
tmpfs 198M 1.1M 197M 1% /run
/dev/vda1 58G 7.9G 51G 14% /
tmpfs 988M 0 988M 0% /dev/shm
tmpfs 5.0M 0 5.0M 0% /run/lock
/dev/vda15 105M 6.1M 99M 6% /boot/efi
tmpfs 198M 4.0K 198M 1% /run/user/0
tmpfs 198M 4.0K 198M 1% /run/user/1003
Inode Consumption (linux)
You can have plenty of disk space but run out of inodes. Check with df -hi
Filesystem Inodes IUsed IFree IUse% Mounted on
tmpfs 247K 710 247K 1% /run
/dev/vda1 7.4M 161K 7.3M 3% /
tmpfs 247K 1 247K 1% /dev/shm
tmpfs 247K 4 247K 1% /run/lock
/dev/vda15 0 0 0 - /boot/efi
tmpfs 50K 26 50K 1% /run/user/0
tmpfs 50K 25 50K 1% /run/user/1003
Once a computer is above 80% disk space usage, there will be problems. Linux computers need 20% free space at all times to help manage and organize their files and inodes. If a linux computer reaches 95% or higher on a root partition it can crash the system completely.
Disk Space Alert
#!/bin/bash
#start editing
mail="user@mail.com"
partition="/dev/sda1"
threshold="80"
#stop editing
percent=$(df -h / | grep "$partition" | awk '{ print $5 }' | sed 's/%//g')
if ((percent > threshold))
then
echo "$partition at $(hostname -f) is nearly full" | mail -s "Your disk is nearly full!!!" "$mail"
fi