Understanding the df command output

Question

Below is an output of df command

# df /boot
Filesystem     1K-blocks   Used     Available Use%  Mounted on
/dev/sda2         122835  26732     89550     23%   /boot

I cannot figure out how the "Available" column is calculated. It doesn't equal:

 1K-blocks - Used

It seems about equal:

(1K-blocks - Used) - ((1K-blocks) * 5 / 100)

My question is, how is the "Available" column calculated?

Does this answer your question? [df -h - Used space + Avail Free space is less than the Total size of /home](https://askubuntu.com/questions/249387/df-h-used-space-avail-free-space-is-less-than-the-total-size-of-home) and https://askubuntu.com/questions/48488/ext4-partition-size-free-space-discrepancies — BeastOfCaerbannog, Aug 27 '22 at 06:02

score 6 · Accepted Answer · answered Oct 25 '20 at 10:08

The "Available" column is calculated properly. It shows the available space.

ext4 partitions have 5% reserve by default for root and system services.

You can check that by tune2fs utility.

So it is correct that available space is all space minus used space minus 5%.

1 Answers1