For review: NAND out of space patch.

[david at lang.hm]

On Mon, 21 Jul 2008, Chris Ball wrote:

> Hi,
>
> Here's a small Python script that acts as a final fail-safe in the event
> that the datastore is full and we can't boot because of it, by deleting
> datastore files largest-first until we cross a threshold of how much
> free space is "enough".  It could be incorporated into the Python init
> process.  (See #7591 for more detail.)
>
> Caveats:
>   * Deleting a file from the datastore doesn't delete its entry in the
>     index.  Resuming a Journal entry with no corresponding file usually
>     produces a blank document in the activity being resumed.
>   * This doesn't try anything outside of the datastore, such as the
>     excellent suggestion of identifying unnecessary large files in the
>     build that could be deleted.  We should of course try that first.
>
> Please review.

I'll go on record repeating the comments made earlier. deleting the 
students largest file is probably deleting their most important work. 
deleting anything the student made should be a last resort (and should 
probably give the student the option of what to delete in the process).

think how devestating it will be to kids to have the term paper they've 
worked on for weeks/months disappear on thembecouse they took one to many 
snapshots, or they played one to many games and triggered the largest 
object getting deleted with no warning.

there are probably things in the journal that can be nuked, becouse they 
can either be re-created (any cached web pages), or are just a record of 
what was done (terminal activities for example), but don't delete anything 
of the students without getting confirmation of what to delete first.

David Lang