For example, an application that does not care about crash recovery or rollback might make the open of a journal file a no-op. SQLite might also add one of the following flags to the xOpen method: It is not used to indicate the file should be opened for exclusive access.
I have been using 5 RPis as a camera with motion detection and post-processing.
This application requires high reliability and it was a pretty long journey until all the issues were solved. Connectivity Of course, the first thing you need is proper connectivity, especially if you have your RPi on a remote location. There are many wifi dongles and most of them are very bad poor signal quality.
This works for me — https: Remote shell Related to the Connectivity.
You need to be able to connect there remotely. It is just for an inspiration, you need to edit it for your setup. Basically after boot or wifi re-connection, RPi connects to my server and starts reverse-port-forwarding so I can access RPi from my server.
That improves life a lot. Bad SD card To survive an unexpected poweroff, you need to have all filesystem mounted read-only more about it later. But first… even if you have your FS read-only, a cheap SD card can destroy the data on the card itself.
Unless you have special requirements, there are only a few paths which needs to be writable. That may complicate the update later… 4.
Install busybox syslog instad. It logs into memory and is very lightweight.
You can then use logread command to read syslog ringbuffer from the memory when needed. Also clock keeping is poor on a standard RPi so you may consider updating time regularly every hour or two should be enough. I used ntpdate for this. DHCP lease is the major problem. Simple solution is to delete the old directory and make it as a symlink to tmp like this: If you use alsamixer to set up volume level, make sure to do so in read-write filesystem.
Watchdog It is useful to set up a watchdog which can reboot your RPi in case something is unresponsive or eating CPU too much.
Setting a minimum free RAM amount is a good idea. Before starting the watchdog, be prepared that you may have configured it wrongly and it will reboot immediately when you start it and may continuously reboot after each boot.
So be prepared to modify your SD card on a different device if that happens. It rebooted my box once while I was doing some filesystem changes. Fortunately it booted fine for me, but it may not for you and may require manual, local fix.
In addition to the watchdog, you should set up reboot after a kernel panic. I think you can somehow enable sending busybox syslog over the network.
I made my own script for this purpose, though.
Simple and helped a few times. If you can ensure it somehow, then fine, use cron. If not and using relative time is enough, you can make a fake cron using bash script, while loop and wait commands.
If you did everything correctly, it will boot just fine. If not, look at syslog and try to find out why. You can fix the SD card in a different computer.
Originally posted by: chrisnei @ashio-midori.com Provided your uninstall does actually delete all your personal files in your personal user data directory then it will work, because the problem is . Don't forget to use WikiFormatting when writing in Trac.. I wonder why the SQLite database is read-only. It should be writeable, assuming you used "sudo" when installing. Attach the ashio-midori.com if that doesn't help you resolve the problem. Stack Exchange network consists of Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share .
What to do next Enjoy your reliable RPi. If you ever want to update the software, just remount the root filesystem as read-write temporarily: Now run your apt-get etc stuff, modify what you need.Database Error | 8 Database Message | attempt to write a readonly database Versions prior to v2 1 might exhibit this error as follows: Discovery fails when run via.
Reply: Joseph Bruni: "Re: sqlite[S8]: attempt to write a readonly database" Contemporary messages sorted: [ by date ] [ by thread ] [ by subject ] [ by author ] [ by messages with attachments ] This is an archived mail posted to the Subversion Users mailing list.
The database may be read-only for several reasons. You can explicitly ask SQLite to open it read-only. The file may be marked for read-only access for your user. Using my Django app, I'm able to read from the database just fine. When the application didn't have permission to access the file, it gave me this error: attempt to write a readonly database Wh.
SQLite - attempt to write a readonly database Hi Experts, I'm using Windows 7, opening an sqlite file in my documents folder with VS and the amalgamation of sqlite (the Reviews: When the new version of the app starts up, the read-only database connection in the native Java code is opened.
When this connection spots the journal, it tries to roll back the journal. And because it’s a read-only connection, it fails.