Shift is cryptocurrency that was launched in August 2015 based on Ethereum by a group of cryptocurrency enthusiast. Shift Storage Cluster - The default state of the IPFS infrastructure is represented as a globally shared network. This can lead to problems when it comes to verifying data integrity, availability, and custom implementation details such as earning token rewards for running a storage node. For this reason, Shift runs a private swarm. The storage nodes use a custom swarm key to ensure that they can only talk to other nodes using the same key. This also prevents Shift nodes being used to host and deliver content that was added outside of the Shift network which should improve reliability and performance.
In order to store data permanently, IPFS implements a concept called pinning. Pinning content means that the content will be available permanently (or until it is unpinned). By default the pinning only applies to a single peer that it is pinned to, but that means if that machine goes offline, the content can be lost. The way around this is by using an IPFS cluster: a subnet (or private net) running the IPFS daemon, containing only Shift peers. The Shift cluster runs as a wrapper around the IPFS daemon. It allows the end user to connect a group of IPFS nodes together so that content can be stored and replicated within the group. The cluster elects a leader to be in charge of keeping track of which content is available in which locations.
The Shift cluster provides a modular clustering system for use with IPFS. This clustering system works in conjunction with the IPFS daemon in order to accomplish the following tasks:
1. Pin, unpin and repin content to peers
2. Provide an HTTP API for communications
3. Assert and follow cluster consensus
4. Replication factor
5. File storage and retrieval
These functions come together to provide an extensible decentralized storage system that operates completely independently from the public IPFS network. This is vital to allow users to insert and persist content within the system.