2022-12-03 12:11:58.409|ERROR|emoncms_mqtt.php|ErrorException: mysqli::query(): (HY000/3): Error writing file ‘/tmp/MYos5EUQ’ (Errcode: 28 “No space left on device”) in /var/www/emoncms/Modules/input/input_model.php:734
Stack trace:
Got this message from the log file. Restarted the system and mosquito but didn’t help.
What can I do?
What version of EmonSD are you running? What is the hardware?
There was an issue a while back with the log files not rotating correctly and filling up the space.
what does df -h tell you?
hi Brian,
I have [low-write 11.0.9] running on an EmonPi.
When I turn on the autorefresh of the emoncms log, I get the message every 1,5sec
Where can I enter the command you mention (d f -h)? I’'m not familiar with this.
thhnx,
Vincent
The df command is entered at the command line. It shows how much disk is free (df, disk free).
You could get similar details by going to the Admin: System Info in the emoncms left menu and looking under the Disk heading. Paste it here for helpers to read, please.
Before I turned to the forum I tried a complete reboot of the system but the message did not disappear.
In the admin page, click on ‘Copy as Markdown’ and paste here (no further formatting required)
no because…
The error is for tmp which is odd.
How old is the EmonPi?
Have you installed anything other than EmonCMS on the EmonPi?
Sorry. You need to SSH into the EmonPi to issue that command on the command line.
emonhub :- Active Running
emoncms_mqtt :- Active Running
feedwriter :- Active Running - sleep 300s 0 feed points pending write
service-runner :- Active Running
emonPiLCD :- Active Running
redis-server :- Active Running
mosquitto :- Active Running
demandshaper :- Active Running
Model :- Raspberry Pi 3 Model B Rev 1.2 - 1GB (Sony UK)
Serial num. :- 4D2CE44B
CPU Temperature :- 58.00°C
GPU Temperature :- 58.0°C
emonpiRelease :- emonSD-21Jul21
File-system :- read-write
To fix this, you will need to SSH into the shell.
I think something has happened such that a process has left some files in the directory that need to be manually removed.
A bit of digging and I find that the /tmp folder should be cleaned regularly by a service called systemd-tmpfiles.
You can check when it was last run with
pi@emonpi:~ $ systemctl list-timers
Mine looks like this.
NEXT LEFT LAST PASSED UNIT ACTIVATES
Sun 2022-12-04 17:07:01 GMT 10min left Sun 2022-12-04 00:03:37 GMT 16h ago apt-daily.timer apt-daily.service
Sun 2022-12-04 17:09:00 GMT 12min left Sun 2022-12-04 16:39:37 GMT 16min ago phpsessionclean.timer phpsessionclean.service
Mon 2022-12-05 00:00:00 GMT 7h left Sun 2022-12-04 00:00:37 GMT 16h ago logrotate.timer logrotate.service
Mon 2022-12-05 00:00:00 GMT 7h left Sun 2022-12-04 00:00:37 GMT 16h ago man-db.timer man-db.service
Mon 2022-12-05 06:08:15 GMT 13h left Sun 2022-12-04 06:09:37 GMT 10h ago apt-daily-upgrade.timer apt-daily-upgrade.service
Mon 2022-12-05 10:38:37 GMT 17h left Sun 2022-12-04 10:38:37 GMT 6h ago systemd-tmpfiles-clean.timer systemd-tmpfiles-clean.service
Checking on my system and I see there were 2 files sitting there that are not being cleaned up - so it does happen. I’ve now removed them.
You need to SSH in and list the files in the /tmp folder and we can see what needs to be deleted.
My /tmp folder currently looks like this.
pi@emonpi:~ $ ls -la /tmp
total 4
drwxrwxrwt 10 root root 200 Dec 4 16:55 .
drwxr-xr-x 21 root root 4096 Oct 17 2019 ..
drwxrwxrwt 2 root root 40 Sep 18 09:17 .font-unix
drwxrwxrwt 2 root root 40 Sep 18 09:17 .ICE-unix
drwx------ 3 root root 60 Nov 25 10:21 systemd-private-36f58b8800834f268c77452ef788441e-apache2.service-Do59qG
drwx------ 3 root root 60 Sep 18 09:47 systemd-private-36f58b8800834f268c77452ef788441e-redis-server.service-IF8TxJ
drwx------ 3 root root 60 Sep 18 09:17 systemd-private-36f58b8800834f268c77452ef788441e-systemd-timesyncd.service-ZIrgqt
drwxrwxrwt 2 root root 40 Sep 18 09:17 .Test-unix
drwxrwxrwt 2 root root 40 Sep 18 09:17 .X11-unix
drwxrwxrwt 2 root root 40 Sep 18 09:17 .XIM-unix
[edit]
Interestingly, it looks like the standard configuration expressly tells the clean process not to clean the tmp folder
pi@emonpi:~ $ cat /usr/lib/tmpfiles.d/tmp.conf
# This file is part of systemd.
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
# See tmpfiles.d(5) for details
# Clear tmp directories separately, to make them easier to override
D /tmp 1777 root root -
As far as I can deduce from the man file, the trailing - means no automatic clean-up is done. 
Is tmp cleared on reboot?
The controlling of clearing is done by this service. Some file (those still in my tmp folder are specifically only removed/updated at boot. So if not cleared on the timer, then no they won’t be cleared on boot (as the OP has discovered).
I checked in the ssh and find the same timers and files as you do. All timers have benn passed in less than 24h
What else is in tmp folder?
Please select the text in the terminal window. Once selected, it is automatically put into the paste buffer (clipboard).
You can then paste it as ‘Preformatted’ text (between 3 backticks) or use the button in the ribbon.
Can you provide the df -h output, please?
pi@emonpi:~ $ ls -la /tmp
total 4
drwxrwxrwt 10 root root 200 Dec 4 21:42 .
drwxr-xr-x 18 root root 4096 Jul 21 2021 ..
drwxrwxrwt 2 root root 40 Dec 2 20:41 .font-unix
drwxrwxrwt 2 root root 40 Dec 2 20:41 .ICE-unix
drwx------ 3 root root 60 Dec 2 20:41 systemd-private-0439c32c8cbb4c8fbb667eee0e61aafc-apache2.service-CvGQfu
drwx------ 3 root root 60 Dec 2 20:41 systemd-private-0439c32c8cbb4c8fbb667eee0e61aafc-redis-server.service-8JI2es
drwx------ 3 root root 60 Dec 2 20:41 systemd-private-0439c32c8cbb4c8fbb667eee0e61aafc-systemd-timesyncd.service-AIpiVR
drwxrwxrwt 2 root root 40 Dec 2 20:41 .Test-unix
drwxrwxrwt 2 root root 40 Dec 2 20:41 .X11-unix
drwxrwxrwt 2 root root 40 Dec 2 20:41 .XIM-unix
pi@emonpi:~ $ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/root 4.1G 2.2G 1.8G 56% /
devtmpfs 430M 0 430M 0% /dev
tmpfs 463M 0 463M 0% /dev/shm
tmpfs 463M 12M 451M 3% /run
tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs 463M 0 463M 0% /sys/fs/cgroup
tmpfs 1.0M 4.0K 1020K 1% /var/lib/php/sessions
tmpfs 1.0M 0 1.0M 0% /var/tmp
tmpfs 30M 26M 4.2M 87% /tmp
/dev/mmcblk0p3 9.9G 87M 9.3G 1% /var/opt/emoncms
/dev/mmcblk0p1 253M 48M 205M 19% /boot
log2ram 50M 11M 40M 22% /var/log
tmpfs 93M 0 93M 0% /run/user/1000
I can’t change the format …
In the ribbon, click on this button (when creating the message)
and paste the text between the 2 sets of backticks (leave them on a line on their own).
I’ve edited the format.
Back to the problem. I’m stumped. tmp has plenty of room, so why you are getting that error is unknown.
All I can suggest is get a new SDCard (you can buy one ready to go) and migrate your data etc.
It could be the card is failing, but that is unusual. @Gwil
PS
I have learnt something so not a complete waste of time 
in my analysis I used 87% of /tmp allready. Which is limited to 30M …
as I’m a starter, there is not valuable data on it. As I’ve some free SD-cards hanging around (of a SLR camera), which is the easiest way to migrate to a new SD-Card
is there a topic on migrating?
will 64G suite my system?
Yes, of course, I was just looking at the files listed.
This is my output and as you can see, apparently the same files but 0% use.
pi@emonpi:/tmp $ ls -la
total 4
drwxrwxrwt 10 root root 220 Dec 4 21:47 .
drwxr-xr-x 21 root root 4096 Oct 17 2019 ..
drwxrwxrwt 2 root root 40 Sep 18 09:17 .font-unix
drwxrwxrwt 2 root root 40 Sep 18 09:17 .ICE-unix
drwx------ 3 root root 60 Nov 25 10:21 systemd-private-36f58b8800834f268c77452ef788441e-apache2.service-Do59qG
drwx------ 3 root root 60 Sep 18 09:47 systemd-private-36f58b8800834f268c77452ef788441e-redis-server.service-IF8TxJ
drwx------ 3 root root 60 Sep 18 09:17 systemd-private-36f58b8800834f268c77452ef788441e-systemd-timesyncd.service-ZIrgqt
-rw-r--r-- 1 root root 0 Dec 4 17:19 test-root.txt
drwxrwxrwt 2 root root 40 Sep 18 09:17 .Test-unix
drwxrwxrwt 2 root root 40 Sep 18 09:17 .X11-unix
drwxrwxrwt 2 root root 40 Sep 18 09:17 .XIM-unix
pi@emonpi:/tmp $ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/root 4.0G 2.6G 1.2G 69% /
devtmpfs 484M 0 484M 0% /dev
tmpfs 488M 0 488M 0% /dev/shm
tmpfs 488M 56M 433M 12% /run
tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs 488M 0 488M 0% /sys/fs/cgroup
tmpfs 1.0M 0 1.0M 0% /var/lib/php/sessions
tmpfs 30M 0 30M 0% /tmp
tmpfs 1.0M 0 1.0M 0% /var/tmp
/dev/mmcblk0p1 253M 52M 202M 21% /boot
/dev/mmcblk0p3 10G 798M 8.7G 9% /var/opt/emoncms
log2ram 50M 5.2M 45M 11% /var/log
tmpfs 98M 0 98M 0% /run/user/1000
You could try sudo ls -la otherwise I do not understand it.
Use this guide to updating Update & Upgrade - Guide | OpenEnergyMonitor
Note, @TrystanLea is about to release a new EmonSD image imminently.