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What is the worst case scenario of a hard shutdown with ubuntu (11.10)? (in other words, turning PSU off)

  • data loss
  • os instability
  • etc
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up vote 2 down vote accepted

To my knowledge, all of the above. When Ubuntu closes without properly shutting down, no filesystems are unmounted, no open handles are closed and any I/O operations will be stopped mid-process. However, Ubuntu is designed to be fairly robust when it comes to unexpected hardware changes. This can lead to data corruption on any of the mounted filsystems (including /) which can lead to system instability, but this is highly unlikely unless you are running apt-get upgrade at the time. If any extra devices were being written to, and the PSU is suddenly cut, then it's possible that these files would become corrupted and unavailable for use.

Of course, this isn't going to happen very often at all, but it should at least be avoided as much as possible. Also, after a hard shutdown where you suspect data may have been vulnerable, try booting it up into a Memtest and into the Recovery mode to try and clean it up before booting properly again.

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I think you are overstating the risks somewhat. The default file system in Ubuntu is designed to protect the metadata in case of crashes. You could very well lose data in files that had pending writes at the time of the crash, but it is unlikely that the whole system will become unstable (assuming you weren't running apt-get upgrade at the time). There is some hardware that might not handle power failures during writes that well though, such as some memory cards and thumb drives. –  James Henstridge Apr 5 '12 at 4:14
    
Edited to reflect new info. Thanks @James !! –  agc93 Apr 5 '12 at 4:33
    
@JamesHenstridge Thanks for the clarification. –  assylias Apr 5 '12 at 7:46
    
For a few reasons I have been forced/accidentally doing hard shut down on my system a couple of times. After the last time I'm beginning to see some problems. Google chrome has become completely useless. It just stalls. Reinstalling it doesn't help. I suspect that the shut down happened while chrome fetched updates. Could be other reason. Although I haven't seen the behaviour before the last hard shut down. –  worldsayshi Apr 25 '13 at 11:32
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