[tahoe-dev] Why no error message when I have only one storage node?

Zooko Wilcox-O'Hearn zooko at zooko.com
Mon Aug 10 08:48:01 PDT 2009


On Monday,2009-08-10, at 9:35 , Ludovic Courtès wrote:

> Zooko Wilcox-O'Hearn <zooko at zooko.com>
> writes:
>
>> On Monday,2009-08-10, at 9:18 , Ludovic Courtès wrote:
>>
>>> Having stored all shares on the user's node, will an eventual
>>> "tahoe deep-check --repair" reshuffle shares to other servers that
>>> have become available in the meantime?
>>
>> That would be ticket #699.  It currently doesn't.  Instead, the deep-
>> check detects that all of the shares are downloadable and quits,
>> happy that everything is right with the world.
>
> Thanks for the explanation.
>
> This issue is indeed critical for a backup use case.

I agree with your opinion that this is a serious issue and that it  
would be really great if someone would fix it, but I'm not sure if I  
would call it "critical", since people can and do use the current  
version of Tahoe-LAFS for backup.  I guess the way they work-around  
this is some combination of (a) don't run a storage server on the  
computer which has the data that they want to back up, and (b) make  
sure that enough good storage servers are connected before doing a  
backup.

Pretty kloogey!  Note that there is a clump of tickets related to  
#699.  I think my personal favorite way to improve this would be for  
someone to fix #573.  I think it would solve your problem as well as  
several other people's problems.  I also would like to see #778  
fixed.  #573 and #778 both seem like easier changes to make than  
#699.  If someone like Kevan Carstensen wanted to get a little deeper  
into Tahoe-LAFS code without getting in *too* deep, I would recommend  
#573 or #778 but not #699.  :-)

Regards,

Zooko

tickets mentioned in this email:

http://allmydata.org/trac/tahoe/ticket/699 # optionally rebalance  
during repair or upload
http://allmydata.org/trac/tahoe/ticket/573 # Allow client to control  
which storage servers receive shares
http://allmydata.org/trac/tahoe/ticket/778 # "shares of happiness" is  
the wrong measure; "servers of happiness" is better


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