Protect your Raspberry PI SD card, use Read-Only filesystem
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Hello there,
Thank you for posting this great tutorial!
I tried following your instructions on both Lubuntu 16.04 and on Ubuntu Mate 16.04 but unfortunately my Raspi3 no longer boots after adding the magic word "ro" on the fstab file.
Everything else seems to be working including the tmpfs commands
Any ideas why this would happen? Do these distros differ fundamentally from Rasbian Jessie?Below are the errors shown on the screen when it hangs:
[34.800508] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
[34.800657] brcmfmac: brcmf_add_if: ignore IF event
[35.852809] brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
[35.853037] brcmfmac: brcmf_add_if: ignore IF eventThanks much!
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Hello again,
I realized what my problem was...I was trying to make the GUI system read only (i.e. without removing the x server stuff). This leads me to a second question: Is it possible to make a basic Debian system with a GUI truly read only (like squashfs for an i386 architecture)? I assume the risks of running out of the 1GB Raspi memory, if only I knew how to get there.
Many thanks -
Hi
If you ever want to go "one step further", then please have a look at my project Nard SDK. Everything runs from RAM. The SD card isn't used at all (except for boot).
http://www.arbetsmyra.dyndns.org/nard/ -
@rln-nard
very interesting, thanks for sharing it
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Hi,
Thank you very much for this tutorial. It helped me a lot! I have one issue that I can't solve by myself! I followed this tutorial step by step on my Raspian Jessie Lite system and it works perfectly...but when I put SD Card into another Raspberry Pi (same model RPi B+), it always boot with the IP (through Ethernet) 169.254.xxx.xxx. To fix it, I have to boot (only one time) without ",ro" in /etc/fstab for the disk "/". Then I can put back ",ro"! Do you think that I have some missing symlinks??
Thanks -
@Bcow7
That's interesting, may be network config has MAC address hard coded and then it can't write the new. Did you tried to switch the SD and the Wifi Dongle at the same time ? (if you're not using eth0 of course) ? -
@Charles
Hi, I'm using eth0 and I don't have any Dongle or shield. I tried to list all modified files modified after I reboot in Read-Write, but I didn't find anything related to the MAC address... :-S -
I've made a couple of scripts for this as I keep needing it for various projects.
These work with the standard desktop and with the chrome browser as I use it for kiosk mode.
The main problem I had was making the file system RO only to realize I needed to install/update something so I've included a script to re-enable RW mode.
Nothing complicated, but they seem to work reliably.
One caviat, if you riu the makerw script when the file system is already RW you'll screw up your OS, I should add a check at the start of the script really...
https://github.com/MarkDurbin104/rPi-ReadOnly -
Hi,
great tutorial, helped me a lot! Hopefully this will end my SD card corruption problems. One thing I noticed is that there is a constant error in syslog:
frequency file /var/lib/ntp/ntp.drift.TEMP: Read-only file system- ntp wants to writedriftfilebut is unable to. I fixed that so thatdriftfilecommand in/etc/ntp.confpoints to/tmp/ntp.drift.# /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help driftfile /tmp/ntp.driftAnother thing - I added loggly integration so I'm able to debug my Pi after reboots when syslogs are gone. I kept
rsyslogand followed this guide (besides Python specific logging it also adds adds syslogs).Some info about driftfile: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/s1-Understanding_the_Drift_File.html
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@Gregor-Ratajc
Thanks for the tip, I updated the tuturial according driftfile -
I also updated to avoid the random-seed file problem
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I've used this multiple times, great resource.
One thing that could be made clearer is the tmpfs additions to fstab, I missed them and couldn't ssh in -
Thanks a lot for this tutorial!
On debian jessie /usr/lib/tmpfiles.d/var.conf chmods /var/spool to 0755. This means that /tmp is changed to 0755 as well because we changed /var/spool to point to /tmp. So the /var/spool line in /usr/lib/tmpfiles.d/var.conf has to be commented out.
/run and /run/lock are tmpfs already, maybe they are better softlink targets than /tmp. -
@Bruce Aldridge
I cannot SSH too, to my RPi. What I did is I created a symlink for sshdln -s /tmp /var/run/sshd
Great article btw Charles! :). Thanks!
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Update: My mistake I missed the sysmlink for /var/run.
No need for my first comment.
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Hello,
There is a (rather new) Olimex single board card with onboard 4GB eMMC MLC/SLC Flash
Do you think this could be an answer to the corruption of data for an always on card ?
(with regular backup...of cours...) or the problem is not related to SD card ???
thx. -
I tried this tutorial twice and both times couldn't SSH in after the final reboot. I found this tutorial a little more helpful - http://petr.io/en/blog/2015/11/09/read-only-raspberry-pi-with-jessie/. I susptec the difference was the part they mentione specifically enables SSH after changing these settings. That tutorial also makes it a little more clear that you have to add three lines in /etc/fstab, not just add ro twice.
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Hi I successfully made my Pi Zero v 1.3 Read Mode, but a problem came up when I was trying to connect to internet with a 3g usb dongle.
First, the modem get connected to internet, but after a minute or less, it losed the connection, and then it reconnects, and the same story was looping forever.
After thinking, the problem was the DNS, because when the modem connects to internet, it changes the default DNS and tried to write the new DNS to the default file, here is the problem, the modem didn't notice that he cant write to the SD!
I took the solution from here: https://github.com/emoncms/emoncms/blob/master/docs/RaspberryPi/read-only.md
touch /tmp/resolv.conf
sudo rm /etc/resolv.conf
sudo ln -s /tmp/resolv.conf /etc/resolv.conftouch /tmp/resolv.conf.dhclient-new
sudo chmod 777 /tmp/resolv.conf.dhclient-new
sudo rm /etc/resolv.conf.dhclient-new
sudo ln -s /tmp/resolv.conf.dhclient-new /etc/resolv.conf.dhclient-newsudo mv /sbin/dhclient-script /sbin/dhclient-script_original
sudo ln -s /home/pi/emonpi/dhclient-script_raspbian_jessielite /sbin/dhclient-scriptThen rebooted and all worked fine, the 3g modem connected to the internet and never disconnected, then I successfully SSH with weaved.com service.
After that another problem came up, my system is a GPS tracker for public transport, so there is a GPS module in my system, and the GPS was not working for the same reason as the 3g modem.
I'm using a "Ublox Neo 6m GPS" and GPSD to get the required information.
When GPSD run at boot it tryes to write a configuration file to open the stream, but it cant because the Pi is in read mode, so we need to put in that file what GPSD write at boot.
To solve this, just edit this file: /etc/default/gpsd
Then edit as this:
START_DAEMON="true"
GPSD_OPTIONS="-n"
DEVICES="/dev/ttyAMA0" #My GPS is connected via UART, change if yours is via USB or whatelse
USBAUTO="true"
GPSD_SOCKET="/var/run/gpsd.sock"Finally reboot and all will work fine.
So, if you are having a problem with a sensor or what else, first verify if the program who communicates with it needs to write sometime to the SD.
Thank you and greetings from Mexico!!!
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Hi !
I've tried to complete tour tutorial but when I do the step "Move some system files to temp filesystem", I've detected that it result on a dbus problem that when the Raspberry is rebooted It can resolve the dhcp and hostname service.
Can anyone help me please?
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need to change UPEX4C_autoconfigfil in /usr/sbin/update-exim4.conf
