I want to simulate a problem some of our servers have had with the filesystem going readonly when connection to the NAS goes down. Is there a quick way to cause the root filesystem to go readonly in a healthy system?

I tried

mount -o ro,remount /dev/sda1

but got

mount: / is busy

If it helps I'm running Debian 6 (Squeeze)

1 Answer 1


Maybe just SysRq+U (force remount all filesystems readonly) will be enough for the test?

If keyboard is not available, it can be done with echo u > /proc/sysrq-trigger


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