[tahoe-dev] [tahoe-lafs] #1252: use different encoding parameters for dirnodes than for files

tahoe-lafs trac at tahoe-lafs.org
Thu Jan 6 06:45:10 UTC 2011


#1252: use different encoding parameters for dirnodes than for files
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     Reporter:  davidsarah     |       Owner:  davidsarah                                        
         Type:  defect         |      Status:  assigned                                          
     Priority:  major          |   Milestone:  1.9.0                                             
    Component:  code-frontend  |     Version:  1.8.0                                             
   Resolution:                 |    Keywords:  preservation availability dirnodes anti-censorship
Launchpad Bug:                 |  
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Comment (by zooko):

 I don't agree with the whole idea. We don't know that a given directory is
 more important than the files it references -- I often reference files
 from a directory which I also have directly linked from other directories
 or from my bookmarks or my personal html files or what have you. And we
 don't know that directories are smaller than files -- sometimes people use
 small files and sometimes people use large directories. I think if you
 have any non-negligible chance at all of losing an object then you have a
 problem, and the solution to that problem is not automated configuration
 in which some objects get more robust encoding than others. That's because
 the default fixed encoding for ''all'' objects should be robust enough to
 make probabilistic loss due to "oops I didn't have enough shares" never
 happen. If you're still having object loss then you have a deeper problem
 than "Oh I needed a more robust encoding.". I also don't like adding to
 the cognitive complexity for users, who already struggle mightily to
 understand what erasure coding means, what the default settings are, how
 the shares are distributed to servers, what happens when you re-upload,
 what happens if you change the encoding configuration, etc., etc. Having
 different types of objects encoded differently is only going to make it
 harder for them to understand and manage their grid and address their
 ''real'' risks of data loss.

-- 
Ticket URL: <http://tahoe-lafs.org/trac/tahoe-lafs/ticket/1252#comment:4>
tahoe-lafs <http://tahoe-lafs.org>
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