As an administrator, you will also need to keep track of available disk space on your
disks.
So let's have a look at the commands that are involved.
To start with, there is the df command.
Df shows the amount of space that is available on mounted devices.
It has different options to determine how you want to see it displayed.
Then there is du, which stands for disk usage.
It's giving a summary, and the nice thing about it is that you can see how much files
you've got in a specific directory.
Now you should notice that these utilities don't work very well on thin provisioned storage,
and that is because thin provisioned storage is pretending to offer more storage than is
really available.
So you might see 20 GB available, where in reality, after writing 5 GB, your thin provisioned
storage might be full.
Let me demonstrate these tools.
So let's use df minus h to start with.
I like the option minus h, because minus h is giving a human-readable format.
So here we can see the most important storage device, which is the LVM Logical Volume Root
on the volume group CS, and it has 13 GB available.
Otherwise, we can see that there is the boot device with 606 MB available.
I just said gigabyte, really it's gigabyte, because gibi, mebi, and so on is the default
display in anything regarding your storage.
Now if you want to see how much files in a directory, use du minus hs on USR, for instance.
Then it needs to calculate a little bit, and here we can see that USR in total has 3.8
GB of storage available.
And that's how you monitor available disk space.