2022-10-16
Found /var/log/collectd.log

Decided to try:
	$ for i in *; do cp $i t; mv t $i; done
	below cmd output started 2022 Sun Oct 16 08:24:05 AM PDT
	above cmd output done    2022 Sun Oct 16 08:24:05 AM PDT
	root@zareason-limbo:/var/lib/collectd/rrd/zareason-limbo/df-mymount-public_html x86_64-pc-linux-gnu 32811

2022-09-26
"make install" solved the problem this time.
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2021-10-25
I cp'd collectd.conf as below.
And I sudo chmod +r /var/lib/collectd/rrd/zareason-limbo/df-*/df_complex-*
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2021-06-30
Maybe this is better?
service collectd restart
I tried /etc/init.d/collectd restart
...a few times, but it didn't seem to help.  As soon as I tried "service collectd restart", public_html started working again.
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collectd.conf goes in /etc/collectd/. - or something like it!

Then:
sudo /etc/init.d/collectd restart

BTW, I had to chmod to make this run as a regular user, and not root:
sudo chmod +r /var/lib/collectd/rrd/zareason2/df-*/df_complex-*

For whatever odd reason, the files are owned by root.root .
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2021-05-01
Bad things happen sometimes even if you do "sudo bash".  I'm guessing there's some bash code that doesn't pass shellcheck :(.
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2020-04-18
If the data stops being collected:
    sudo bash
    /etc/init.d/collectd restart
Bad things seem to happen if you combine those into one step.  Specifically, ssh goes down - perhaps others.