Solana Activates Alpenglow, Targeting 150ms Finality

Solana activated its Alpenglow consensus protocol on mainnet on Oct. 21, replacing TowerBFT and targeting transaction finality in about 150 milliseconds, according to the Solana Foundation’s upgrade details. The Foundation says TowerBFT took about 12.8 seconds to make transactions irreversible.

The handoff began in epoch 1064 at about 13:36 UTC. The Foundation says the final TowerBFT block was slot 459,652,999, certified by 446 of the network’s 654 validators; Alpenglow consensus took over at slot 459,653,000.

How does Alpenglow change Solana’s consensus?

Alpenglow moves validator votes out of transaction blocks and has validators send votes directly to one another, then combine them into certificates. The change is intended to finalize blocks after one or two voting rounds, according to the Solana Foundation.

That makes finality faster than TowerBFT’s process of accumulating votes across 32 slots. The Foundation says transaction execution, programs and fees remain unchanged, while vote transactions no longer appear in blocks.

What comes after the mainnet activation?

The current activation covers Votor, Alpenglow’s voting protocol; Rotor, a planned replacement for Solana’s Turbine block data system, has no scheduled release, the Foundation says. Validators must run a supported Agave-based client and keep at least 0.8 SOL above the vote account’s rent-exempt minimum to pay the Validator Admission Ticket fee.

Decrypt reported that Anza CEO Brennan Watt called the upgrade the most ambitious blockchain upgrade since Ethereum’s Merge. The Decrypt report also says validators completed testing and migration rehearsals before the mainnet switch. The Foundation’s next listed step is Rotor, with timing still unannounced.

Source material

• Solana Foundation’s upgrade details — solana.com
• Decrypt report — decrypt.co