[volunteergrid2-l] Revisiting space contribution caps

[Jody Harris]

It's important to keep in mind that the amount of usable data per user is
limited by the minimum node size and the number of nodes, not the amount of
space a user contributes.

S = Min Node Size
N = Number Of Nodes
U = Number Of Users
E = Expansion Factor (7:15 - 2.2)
A = space available per user

Something in the range of:

A = (S * N)/(U * E)

.... I think... and that gives us some buffer space.

----
- Think carefully.


On Thu, Feb 3, 2011 at 9:33 AM, Jody Harris <jharris at harrisdev.com> wrote:

> Shawn, I've been thinking about our policy of capping sizes in light of our
> discussion of the possibility of removing the share expire settings....
>
> IF the smallest node is controlled (!<500 GB), and the smallest and oldest
> nodes are not getting close to being filled, then there really is no sense
> in limiting the upper limit of node sizes.
>
> As long as there is sufficient space on the node with the least available
> space, tahoe will not distribute shares unevenly across nodes.
>
> Thus, I think we can safely remove our max-size policy without any impact
> on the grid. Our concern then shifts to simply monitoring the smallest nodes
> and making sure those are upgraded to larger drives or removed from the grid
> as content grows.
>
> Does this make sense, or did I overlook something?
>
> jody
> ----
> - Think carefully.
>
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