> For the complete documentation index, see [llms.txt](https://docs.optimumsec.xyz/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.optimumsec.xyz/coding/unstructured-storage.md).

# Prefer Unstructured Storage for Upgradeable Contracts

Linear storage, which is the default way to manage storage variables, is intuitive but has limitations. When combined with inheritance, it requires us to maintain the well-known (and some would say infamous) [`__gap` array](https://docs.openzeppelin.com/upgrades-plugins/1.x/writing-upgradeable#storage-gaps). Managing this array increases complexity and makes audits more challenging.

A proposed alternative is to use [EIP-7201](https://eips.ethereum.org/EIPS/eip-7201) storage slots, which can offer greater flexibility. However, this approach should be used with caution: variable names should be uniquely chosen and consistently referenced. Utilizing [spelling checkers](https://github.com/optimumsec/the-complete-guide-to-securing-web3-protocols/blob/main/coding/use-spelling-checkers.md) can help maintain naming consistency and reduce potential issues.