The persistent storage layer for all Solana accounts. AccountsDB stores account data in memory-mapped AppendVec files, indexed by pubkey and slot. It supports fast lookups, handles account deduplication across slots, and periodically cleans up dead accounts. AccountsDB is the largest consumer of validator disk space.
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The persistent storage layer for all Solana accounts. AccountsDB stores account data in memory-mapped AppendVec files, indexed by pubkey and slot. It supports fast lookups, handles account deduplication across slots, and periodically cleans up dead accounts. AccountsDB is the largest consumer of validator disk space.
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Think of it as part of the chain machinery that keeps ordering, execution, or consensus moving.
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Consensus, leader rotation, slots, epochs, and the runtime.
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AccountsDB (accounts-db) Category: Core Protocol Definition: The persistent storage layer for all Solana accounts. AccountsDB stores account data in memory-mapped AppendVec files, indexed by pubkey and slot. It supports fast lookups, handles account deduplication across slots, and periodically cleans up dead accounts. AccountsDB is the largest consumer of validator disk space. Aliases: AccountsDb Related: Bank, Snapshot, AppendVec
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An in-memory representation of the accounts state at a specific slot. Each slot gets its own Bank that inherits from its parent slot's Bank. The Bank processes transactions, updates account balances, and tracks execution results. Once a slot is complete, the Bank is frozen and can be snapshotted or used as a parent for the next Bank.
A serialized copy of the full accounts state at a rooted slot, used for fast validator bootstrapping. Full snapshots contain all accounts; incremental snapshots contain only accounts modified since the last full snapshot. New validators download a snapshot instead of replaying the entire ledger history, reducing sync time from days to minutes.
A memory-mapped, append-only file used by AccountsDB to store account data. Each AppendVec corresponds to a specific slot and contains serialized account entries (pubkey, lamports, data, owner, etc.). AppendVecs are immutable once the slot is rooted, enabling efficient snapshotting and cleanup.
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The Rust-based Solana validator client maintained by Anza (formerly Solana Labs). Agave is the original and most widely deployed validator implementation. It handles all aspects of validation: TPU, TVU, gossip, AccountsDB, and RPC. The name 'Agave' was adopted to distinguish it from the Firedancer client.
A next-generation consensus protocol proposed in SIMD-0326 that aims to collapse Solana's legacy systems (Proof of History, Tower BFT, gossip-based vote propagation) into two streamlined mechanisms: Rotor for data propagation and Votor for off-chain voting. Alpenglow targets reducing transaction finality from ~12.8 seconds to under 150 milliseconds, representing the most significant consensus overhaul in Solana's history.
A development organization that spun out of Solana Labs in early 2024 to independently maintain and develop the Agave validator client and core Solana toolchain. Anza also maintains the @solana/kit SDK (formerly web3.js v2), the Anchor framework, and the SVM API. The spin-off was intended to decentralize Solana's core development and improve client diversity.
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An in-memory representation of the accounts state at a specific slot. Each slot gets its own Bank that inherits from its parent slot's Bank. The Bank processes transactions, updates account balances, and tracks execution results. Once a slot is complete, the Bank is frozen and can be snapshotted or used as a parent for the next Bank.
A serialized copy of the full accounts state at a rooted slot, used for fast validator bootstrapping. Full snapshots contain all accounts; incremental snapshots contain only accounts modified since the last full snapshot. New validators download a snapshot instead of replaying the entire ledger history, reducing sync time from days to minutes.
A memory-mapped, append-only file used by AccountsDB to store account data. Each AppendVec corresponds to a specific slot and contains serialized account entries (pubkey, lamports, data, owner, etc.). AppendVecs are immutable once the slot is rooted, enabling efficient snapshotting and cleanup.
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A clock mechanism that cryptographically proves the passage of time between events. PoH uses a sequential SHA-256 hash chain where each output becomes the next input, creating a verifiable ordering of events without requiring consensus. The leader produces ~400,000 hashes per slot (~400ms), and any validator can verify the sequence in parallel, enabling Solana's high throughput by removing the need for validators to agree on time.
Solana's custom BFT consensus algorithm built on top of Proof of History. Tower BFT uses PoH as a clock to reduce communication overhead in traditional PBFT from O(n²) to O(n). Validators vote on forks with exponentially increasing lockout periods—each consecutive vote doubles the lockout, making rollbacks progressively more expensive. A fork is finalized when it reaches supermajority (66.7%+ of stake).
A time window during which a designated leader validator can produce a block. Each slot lasts approximately 400 milliseconds. Slots are numbered sequentially from genesis and grouped into epochs of 432,000 slots (~2-3 days). Not every slot produces a block—a skipped slot means the leader was offline or too slow.
A set of entries produced by a leader during a single slot. A block contains transactions bundled into entries, each with a PoH hash proving ordering. Blocks are broken into shreds for network propagation via Turbine. Maximum block size is limited by compute units (48M CU cap per block) rather than byte size.