[tahoe-lafs-trac-stream] [Tahoe-LAFS] #613: sometimes a helper hurts instead of helping (if you need to upload less than K shares)

[Tahoe-LAFS]

#613: sometimes a helper hurts instead of helping (if you need to upload less
than K shares)
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     Reporter:  zooko    |      Owner:
         Type:           |     Status:  new
  enhancement            |  Milestone:  undecided
     Priority:  major    |    Version:  1.3.0
    Component:  code-    |   Keywords:  upload repair helper performance
  network                |  bandwidth
   Resolution:           |
Launchpad Bug:           |
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Changes (by lpirl):

 * cc: tahoe-lafs.org@… (added)


Comment:

 I thought about this too. Without knowing too much about the internals,
 here is the idea:

 Let's assume the helper knows (better) which shares to upload and which to
 reuse.
 Couldn't an uploader

 1. ask the helper for it's encoding parameters,
 1. do the encryption and the erasure coding,
 1. then send the hashes of the resulting shares
 1. and finally upload those shares, the helper reports as missing?

 Additionally, if a share is unhappy, the helper could fetch it from a
 faster sever and re-distribute it (although it is probably a difficult
 decision if this is beneficial or not).

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Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/613#comment:4>
Tahoe-LAFS <https://Tahoe-LAFS.org>
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