So I was having a similar problem where i was getting the following:
$ vnstat -i eno1
eno1: not enough data available yet
I also tried every other command while pointing to eno1. I would sometimes even get:
Error: Unable to create database backup "/var/lib/vnstat/.eno1"
OR
Segmentation fault (core dumped)
I tried reinstalling, and everything else under the sun.
Following Andrew's answer to the 't' returned:
Error: Unable to open database "/var/lib/vnstat/eno1" for writing: Permission denied
so instead I did the following, but I'm not sure which one of these commands did the trick.
$ sudo vnstat -i eno1 -u
$ sudo vnstat -u -i eno1
Then I checked to see if the interface was working again:
$ sudo vnstat -i eno1
which returned:
>
Database updated: Wed Dec 5 10:17:37 2018
(eno1) since 1969-12-31
rx: 2 KiB tx: 1 KiB total: 3 KiB
monthly
rx | tx | total | avg. rate
------------------------+-------------+-------------+---------------
Dec '69 2 KiB | 1 KiB | 3 KiB | 0.00 kbit/s
------------------------+-------------+-------------+---------------
estimated -- | -- | -- |
daily
rx | tx | total | avg. rate
------------------------+-------------+-------------+---------------
today 2 KiB | 1 KiB | 3 KiB | 0.00 kbit/s
------------------------+-------------+-------------+---------------
estimated -- | -- | -- |
Now its finally able to read and write to eno1 log. I noticed this problem since conky was not showing up any stats reports on today && Month && total. I wasn't expecting anything under month, but after a couple days I was expecting something under hours.
I realise the rest will take a while to populate with data. But now I know for sure it is working. Also, my conky app is finally displaying the information.
However, prior to this solution, I had already chmod the file.
Additional info for newbies such as myself:
- make sure to check which interface you are using, I often see solutions for eth0 and others that do not appear when using "$ ifconfig". Enter:
$ ifconfig
and you should see on the left hand side of the results the interface name. Mine are, eno1, lo, and wlo1.
next to the label: "Link encap:" it should say if it is wireless, ethernet, or local loopback
lo is the local loopback a.k.a localhost/127.0.0.1
What I am not sure of, in my case, is the difference between eno1 and wlo1. they both say "Ethernet". I wonder if doesn't have something to do with my direct wifi printer.