[tahoe-dev] A simple 2 nodes replication

[David-Sarah Hopwood]

On 14/02/13 17:26, Greg Troxel wrote:
> 
> thierry dijoux <tjr.dijoux at gmail.com> writes:
> 
>> After some investigations rebalance seems to work.
> 
> Your example doesn't show that.
> 
>> Here is the test :
>>
>> stop the 2nd node.
>> Upload a file on node 1.
>> Starting node 2 and do a "check --repair" => nothing.
>> Now, in node1, rm .tahoe/storage/shares/de/derbnumtsxwu7rhydpxtxizd5y/1 and
>> do a check --repair, the file is created on node2.
> 
> But that isn't "rebalancing", which would describe the process of
> checking files to see if any do not meet the balance criteria (as shown
> by shares.happy).  That was recovering from missing shares.  I suspect
> if you did the repair while node2 was down that you'd be back where you started.

That's correct.

>> I supposed the files named 0 and 1 corresponding to the index of node (in
>> my case 0 => node1 and 1=>node2)
> 
> I think the files in storage are the share #.

Also correct.

>> May i right or wrong ? I've only got 4 files, so it was "easy", but how to
>> achieve this with tons of files ?
> 
> What's needed is a way to have deep-check --repair consider a file
> unheatlhy if it does not meet some distribution criteria.
> 
> You might try setting shares.happy to 2 instead of 1.
> 
> The real trouble is that this line of thinking leads to incremental
> complexity.  Next one wants one distribution criteria for "good enough
> to place a file" and another for "good enough that we don't try to make
> it better".

The currently proposed algorithm is in
<https://tahoe-lafs.org/trac/tahoe-lafs/ticket/1130#comment:12>.

-- 
David-Sarah Hopwood ⚥

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 555 bytes
Desc: OpenPGP digital signature
URL: <http://tahoe-lafs.org/pipermail/tahoe-dev/attachments/20130215/d6ac4a19/attachment.pgp>