It's not really possible to shard an individual blockchain, because the chain of header hashes depends on all the content in the blocks, and is what makes that content secure. However you can certainly run multiple blockchains in parallel, between the same servers, and even share identities across them by using the same addresses (just make sure all the blockchains' parameters match for the four detailed on this page:
https://www.multichain.com/developers/address-key-format/). You can also just embed hashes to data in the blockchain, and have that data retrieved from outside the chain, for example via a distributed hash table. Or to take things even further, just embed merkle tree roots in the blockchain, enabling a single hash to represent a limitless amount of data.
