Thoughts on The Case for OneSwarm

I should've posted this entry a while ago. This is a talk that Tom Anderson gave at MSR in Mountain View on 9/29/2009.

Summary:

Cloud computing has many issues:

• Data can be locked in (Facebook, ...)
• Need to trust providers with data
• Cloud is a natural monopoly:
• The business model is to attract developers then the users. So the users have no choice.
• Reliability and the ability to handle flash crowds is a high barrier to entry.
• There is no plausible avenue for an open source Cloud. Somebody needs to pay for the infrastructure, so somebody needs to be making money off of it to be sustainable, and the way to do this is through data lock-in and/or data mining...
• Since all data is stored somewhere centrally, it's easier to censor it

Can we use a P2P system instead where users can donate some of their resources to be able to use other people's resources? At first glance, it looks like this might be alright. P2P systems

• have high availability -> But in fact this is not true because seeds disappear
• have no bottlenecks -> But their could be network inefficiencies or ISP throttling
• have no centralized monitoring -> But it's actually easy to track users

The alternative is OneSwarm. OneSwarm has no centralized trust. The idea is to use privacy-preserving sharing where you build a web of trust through friends. Then when a user makes a query, the query goes through friends, then friends of friends, and so on... and the data travels on the reverse path back to the user. Nodes are not supposed to reveal information about where a query they pass along came from, so the receiver of a query cannot relate a user to a query.

The system, is by Tom's admission, vulnerable to collusion, but that's okay. The system is not designed for complete security but rather as a compromise between security, flexibility, and performance. Another assumption is that there is no partitioning in the network and that eventually everyone will be connected, and everyone will have access to everything (which will probably end up happening anyway).

The network of friends is organized as a DHT. To maintain availability and solve the issues with traditional P2P systems, they invented a new type of DHT that is highly scalable and reliable. groups of nodes are organized into tight groups that are replicated via Paxos. Each group then appears as a single node in the DHT.

As a final note, I had a chat with Tom after the talk. He has a pessimistic outlook on what will eventually happen. Mainly, that cloud providers will always end up creating a monopoly using data lock-in and be able to mine the data stored on the cloud, because they will manipulate the API so they can do so.

Likes:

I like OneSwarm. In particular, I liked the DHT implementation. They had some really cute ideas there. It is not a security protocol, it is a "casual" privacy protocol that presents a minimum barrier to snooping. However, if someone wants to get to my data and to know what requests I am making, they would be able to do so.

The availability of a P2P system that is presented as cloud storage on top which users can implement "free" applications, such as an open-source Facebook.

Dislikes:

• I'm not sure I agree with the pessimistic view. Google has started a movement called the data liberation front to basically free users from data lock-in, and I expect this movement to become more important.
• There are more reasons than just convenience for applications to run in a data center. If we move from DCs to P2P systems for storage, we will get much higher lookup costs, and it is not clear systems will scale.
• There are no guarantees of connectivity. The social network might get partitioned, limiting the available data.