[tahoe-dev] [tahoe-lafs] #970: webapi PUT via multiple nodes can cause directory corruption but does not report UncoordinatedWriteError

tahoe-lafs trac at allmydata.org
Tue Feb 23 13:32:57 UTC 2010


#970: webapi PUT via multiple nodes can cause directory corruption but does not
report UncoordinatedWriteError
-------------------------------+--------------------------------------------
 Reporter:  stott              |           Owner:  nobody   
     Type:  defect             |          Status:  new      
 Priority:  minor              |       Milestone:  undecided
Component:  code-frontend-web  |         Version:  1.5.0    
 Keywords:  error usability    |   Launchpad_bug:           
-------------------------------+--------------------------------------------

Comment(by zooko):

 Hm, the docs in [source:docs/specifications/mutable.txt at 3696#L48] suggest
 the following four strategies:
  * don't give the read-write URI to anyone else. Dirnodes in a private
    directory generally satisfy this case, as long as you don't use two
    clients on the same account at the same time
  * if you give a read-write URI to someone else, stop using it yourself.
 An
    inbox would be a good example of this.
  * if you give a read-write URI to someone else, call them on the phone
    before you write into it
  * build an automated mechanism to have your agents coordinate writes.
    For example, we expect a future release to include a FURL for a
    "coordination server" in the dirnodes. The rule can be that you must
    contact the coordination server and obtain a lock/lease on the file
    before you're allowed to modify it.

 Then later they mention that a Tahoe-LAFS gateway automatically serializes
 requests that go through it to the same mutable file or directory. Perhaps
 that should be promoted to a fifth strategy: make all your writes to a
 certain mutable file or directory go through a certain Tahoe-LAFS gateway.

-- 
Ticket URL: <http://allmydata.org/trac/tahoe/ticket/970#comment:5>
tahoe-lafs <http://allmydata.org>
secure decentralized file storage grid


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