Sui's storage fee model ensures that validators can maintain their infrastructure and build a fund to enhance the stability of the network. In a previous article about Sui gas fees, we mentioned the storage fee part of Sui gas fee calculation. The storage fee refers to the economic cost of storing data on the Sui network.
Storage fees for Sui remain fixed, and at the time of writing, are set at 76 MIST per storage unit, or 0.0000076 SUI.
Sui’s strong support for on-chain data makes storage fees an important part of its token economics. However, the overall design simplifies the problem by charging the storage fee as part of the gas fee, a one-time fee for permanent storage. In addition, users will receive rebates when they delete data they own from Sui.
Storage fee calculation
While governance recommends setting storage fees periodically, there are some potential complexities in data storage measurement, with Sui calculating storage fees per storage unit in a transaction.
Each byte of data equals 100 storage units, so one kb equals 1 million storage units. For example, if we have a transaction involving a 1kb NFT, then at the price mentioned above, the storage fee will be equal to 76 million MIST, or 0.076 SUI.
The gas fee for each transaction is included in the relevant storage fee. Taking a 1kb NFT as an example, the total gas fee will include 76 million MIST storage fees. If the NFT is deleted from Sui, it will stop using storage resources and the original storage A portion of the fee (currently set at 99%) will be returned to the gas fee payer as a rebate.
storage fund
With storage fees collected during transactions going into a storage fund rather than being allocated directly to independent validators supporting the network infrastructure, the model recognizes that future validators will need to maintain storage of assets processed by validators that may no longer be located in in the network.
Assets from the storage fund are staked to validators, and rewards earned from staking are paid to validators to offset the cost of storing data on Sui. The direct correlation between data storage and storage fund growth means that as storage needs increase, so will the returns on staking, and this mechanism ensures that as validators’ costs increase, so do their incomes.
Utilizing staking rewards instead of storage fund funds makes the storage fund a self-supporting function of Sui, continuously collecting storage fees from every network transaction and paying kickbacks to users who remove data from the network.
Stable Token Economics
Sui’s token economics model is designed to be self-sustaining, and the storage fee mechanism is designed to achieve this. The size of the fund directly reflects the amount of data stored on the network, as fees accumulate, and by design neither skyrocketing nor falling with experience, the storage fund creates its own gravity, supporting the many validators running the network.
Governance recommendations will set new storage fees from time to time based on various external factors and introduce human factors as needed to correct the model. As the cost of data storage infrastructure decreases, so will storage expenses. Likewise, an increase in the value of SUI tokens may require a reduction in storage fees.