Core Protocol

Snapshot

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.

IDsnapshot

Plain meaning

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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.

Mental model

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Think of it as part of the chain machinery that keeps ordering, execution, or consensus moving.

Technical context

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Consensus, leader rotation, slots, epochs, and the runtime.

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Snapshot (snapshot)
Category: Core Protocol
Definition: 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.
Related: AccountsDB, Bank, Validator
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Concept graph

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Branch

AccountsDB

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.

Branch

Bank

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.

Branch

Validator

A node that participates in the Solana network by validating transactions, voting on blocks, and (when selected as leader) producing new blocks. Validators run the Agave, Firedancer, or Jito client software, require significant hardware (128+ GB RAM, high-core CPU, NVMe SSD), and earn rewards from inflation and transaction fees.

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Core Protocol

AccountsDB

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.

Core Protocol

Bank

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.

Core Protocol

Validator

A node that participates in the Solana network by validating transactions, voting on blocks, and (when selected as leader) producing new blocks. Validators run the Agave, Firedancer, or Jito client software, require significant hardware (128+ GB RAM, high-core CPU, NVMe SSD), and earn rewards from inflation and transaction fees.

Core Protocol

Solana Virtual Machine (SVM)

The Solana Virtual Machine—the execution environment that runs on-chain programs. SVM loads SBF bytecode, provides syscalls for account access and cryptographic operations, enforces compute budgets, and manages memory. The SVM is being modularized (via the SVM API) to enable use in rollups and other environments outside the main Solana validator.

Commonly confused with

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Core Protocolsealevel

Sealevel

Solana's parallel transaction execution engine. Sealevel can process thousands of transactions simultaneously by analyzing each transaction's declared account inputs—transactions that don't touch the same writable accounts run in parallel across available CPU cores. This account-level parallelism is what enables Solana's high throughput.

AliasSVM Runtime
Core Protocolshred

Shred

The smallest unit of block data propagated through the network via Turbine. Blocks are split into shreds of up to 1,228 bytes each (fitting in a single UDP packet). Shreds are Reed-Solomon erasure coded—typically 32 data shreds produce 32 recovery shreds—so blocks can be reconstructed even if up to half the shreds are lost.

Core Protocolslot

Slot

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.

Related terms

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Core Protocolaccounts-db

AccountsDB

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.

Core Protocolbank

Bank

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.

Core Protocolvalidator

Validator

A node that participates in the Solana network by validating transactions, voting on blocks, and (when selected as leader) producing new blocks. Validators run the Agave, Firedancer, or Jito client software, require significant hardware (128+ GB RAM, high-core CPU, NVMe SSD), and earn rewards from inflation and transaction fees.

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Core Protocol

Proof of History (PoH)

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.

Core Protocol

Tower BFT

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).

Core Protocol

Slot

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.

Core Protocol

Block

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.