[tahoe-dev] [tahoe-lafs] #283: implement mutable-file upload/download helpers

tahoe-lafs trac at tahoe-lafs.org
Wed Jul 21 16:35:12 UTC 2010

#283: implement mutable-file upload/download helpers
     Reporter:  warner        |       Owner:                                
         Type:  enhancement   |      Status:  new                           
     Priority:  major         |   Milestone:  undecided                     
    Component:  code-mutable  |     Version:  0.7.0                         
   Resolution:                |    Keywords:  mutable helper upload download
Launchpad Bug:                |  

Comment (by zooko):

 But despite its potential use for #868, I'm -1 on this ticket. I think of
 the existence of the current immutable file upload erasure-coding helper
 as doubling the engineering costs of improving immutable upload. Inventing
 helpers for mutable files and for download would multiply this problem. On
 the other hand, I'm pretty enthusiastic about tickets like #993 (refactor
 download interfaces to treat immutable files and mutable versions more
 uniformly), which offer to reduce the number of codebases that we're
 maintaining and improving.

 I recognize that immutable upload helper offers a performance benefit that
 the current immutable file upload code doesn't. I'm not proposing to kill
 it, which would be a regression for people who use that performance
 benefit. But I hope that we'll improve the normal upload, repair, and
 rebalancing features to such a point that it becomes better for users to
 rely on those features and they stop needing the upload helper.

 Ways that we can improve those things: better and more customizable
 [wiki:ServerSelection share placement], #610 (upload should take better
 advantage of existing shares), #809 (Measure how segment size affects
 upload/download speed.), #873 (upload: tolerate lost or missing servers),
 #1130 (Failure to achieve happiness in upload).

 repair-and-rebalance behavior: #232 (Peer selection doesn't rebalance
 shares on overwrite of mutable file.), #483 (repairer service), #450
 (checker / repair agent), #543 ('rebalancing manager'), #643
 (Automatically schedule repair process), #699 (rebalance during repair or
 upload), #711 (repair to different levels of M), #1004 (how to fix
 'multiple versions are recoverable'?).

 See also [http://tahoe-lafs.org/pipermail/tahoe-dev/2010-July/004718.html
 the discussion on tahoe-dev] that prompted me to write this comment.

Ticket URL: <http://tahoe-lafs.org/trac/tahoe-lafs/ticket/283#comment:5>
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