The idea of allowing new nodes only when X% of nodes are full seems like it could possibly give us some grief. Filecoin has provided us with a very useful experiment demonstrating why there may be some troubles.
In the first 50 days of the filecoin network ~1 PiB has been stored (source). ~1 EiB is available for storage (source).
There are currently 786 filecoin nodes.
This would give 1.3 TiB storage per node (1024 TiB / 786, assuming the 1 PiB figure includes all redundancy).
745 out of 786 (94.8%) of filecoin nodes have more than 1.3 TiB of storage (there’s a list of node sizes here).
217 out of 786 (27.6%) of filecoin nodes have more than 1 PiB storage and could store the whole of filecoin data.
If we took filecoin storage distribution as it is now and applied Safe Network rules to it, it would take a very long time before any new nodes would be allowed to join.
There’s some considerations for this comparison though…
Storage on Safe Network could be cheaper than filecoin so it would fill the spare space faster and reach an equilibrium sooner. This is fine, I accept the reasoning, but filecoin is already usually 20x cheaper than major cloud storage, so why does filecoin see only 0.1% storage utilisation? I’m not convinced that being cheaper means we’ll achieve better distribution.
If the top filecoin nodes broke their single massive nodes into many smaller ones they would have most of them not allowed onto the network. I’m not exactly sure how the logic goes, but with 99.9% unused space virtually all nodes on the network can continue to accept new data for a very long time. Doing a maybe over-simplified analysis, let’s say 0.1% full in 50 days means it would take another 50,000 days to fill the remaining 99.9% of storage (assuming no additional storage came online). That’s 136 years of spare capacity.
Filecoin has separate mechanisms for storage space and uploading and pricing, which allows a lot of spare space to come online very quickly. Safe Network doesn’t have this, it links pricing and spare storage space and uploading all in together. So I’m not sure how the difference in pricing / storage / utilization functions for these two networks will show themselves in the real world.
We’re really lucky that filecoin has shown us the utilization rate. If we’d only seen the uploads of 1 PiB in 50 days we’d say ‘nice work filecoin’ but we are lucky to also be able to see 1 EiB of unused space which gives us some real head scratching to do. In our network we won’t get to see how much spare space there is, so we have no idea how long it might be until the 50% full nodes mark will be reached.
My main worry is (to use an exaggerated example) if we end up with the top 10 nodes of filecoin as the first 10 nodes in Safe Network (between 23 PiB and 71 PiB in size) we’ll be waiting a very long time for new nodes to be allowed to enter the network because it would take a very long time to fill 50% of those nodes.
Should we be worried about the huge amount of spare storage out there hindering growth and node membership? I’m not sure but filecoin makes me feel we should consider things carefully, they have a really huge amount of spare space.