[tahoe-dev] Share distribution (was: tree thawed for post-1.8.2 development)

[Jan-Benedict Glaw]

On Tue, 2011-02-01 11:20:52 +0100, Jan-Benedict Glaw <jbglaw at lug-owl.de> wrote:
> On Mon, 2011-01-31 22:32:48 -0800, Brian Warner <warner at lothar.com> wrote:
> >  * fixes to upload-happiness
> 
> I once saw an email (or an ticket entry) addressing share balancing.
> If I remember correctly, the author suggested to spread shares by
> giving each node a number of key/value pairs and spreading the shares
> so that the number of two nodes having a common value for any key is
> minimal. That bad description may be supplied by an example:
> 
> 
> # Node 1
> datacenter=1
> rack=17
> HE=1
> power_supply_chain=2
> 
> # Node 2
> datacenter=1
> rack=17
> HE=3
> power_supply_chain=2
> 
> # Node 3
> datacenter=1
> rack=17
> HE=2
> power_supply_chain=1
> 
> 
> In this example, the first two nodes share a common UPS, while node 3
> is on a different one. (Other than that, they're in the same rack in
> the same datacenter.)  In this example, if you had to distribute two
> shares, these should go to (node 1 or node 2) and node 3, but not to
> node 1 and node 2, because they share three common tag/values, while
> the other combination only shares two with the others.
> 
> As said, that was another person's idea, but I cannot find a
> reference. Though it would be nice to implement, because users would
> gain more control over share distribution. (Would even be nice for
> running multiple nodes on one machine with several filesystems.)

Doesn't anybody have a clue who suggested this scheme of choosing
nodes for share distribution? Or did the subject distract people from
reading?

MfG, JBG

-- 
      Jan-Benedict Glaw      jbglaw at lug-owl.de              +49-172-7608481
Signature of:              Fortschritt bedeutet, einen Schritt so zu machen,
the second  :                   daß man den nächsten auch noch machen kann.
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