roots changed erratically from rw to ro without any observable reason

[Sil68]

I've gut my GuruPlug Server Standard (running Debian 5.0 Lenny out of the box) up & running since several weeks, and I have to admit, I am really positively surprised by this little box of wonders!

One thing though causes some headaches, namely during regular operation as a web server, and without any observable interference from anywhere, all of a sudden the root filesystem turns from rw-mode to ro-mode, thus causing some issues.

When looking through the cron jobs and the various startup scripts, I fail to find any indication in relation to such a change.

[birdman]

 cron jobs and start-up scripts aren't going to show anything.  They are static scripts.

You need to look at the system log files - the things in /var/log, especially the messages file.

If there is a serious error on a file-system the OS will switch it to read-only to prevent any further damage.  So look for file-system errors on the relevant file-system or hardware errors on the device.