Block size limit controversy

• More transactions per second
• Off-chain solutions are not yet ready to take off the load from the main blockchain.

• Increased blocksize will leave space for extensions like Mastercoin, Counterparty, etc.
  • Neutral: Bitcoin competitors will have lower fees
  • Negative: Bitcoin full nodes are forced to use more resources that don't support Bitcoin
• Small blocks eventually will require higher fees for fast confirmations.
  • Positive: It will no longer be cheap to spam transactions such as Satoshi Dice bets
  • Positive: Fees will not be zero. This is eventually a necessity in order to incentivize miners and secure the mining ecosystem
  • Negative: Bitcoin may look unattractive to new users with high fees
  • Negative: High fees may stop or reverse global adoption, investment, development, support and centralization^{[clarification needed]}
  • Negative: Bitcoin users pay higher fees
• A low blocksize limit encourages higher transactions fees to incentivize miners ("let a fee market develop").
  • A fee market naturally develops due to miner latency regardless[4]
    • The relay network can be optimized so that miners don't have a stale rate increasing with latency. This should cause the fee market to once again require a block size limit to exist.

• A hard fork requires waiting for sufficient consensus.
• Risk of catastrophic consensus failure[5]^{[clarification needed]}
• An emergency hard fork that can achieve consensus can be deployed on a short time period if needed.[6]
• Orphan rate amplification, more reorgs and double-spends due to slower propagation speeds.
• European/American pools at more of a disadvantage compared to the Chinese pools^[why?]
• "Congestion" concerns can be solved with mempool improvements including transaction eviction.
• No amount of max block size would support all the world's future transactions on the main blockchain (various types of off-chain transactions are the only long-term solution)
• Fast block propagation is either not clearly viable, or (eg, IBLT) creates centralised controls.

On October 3, 2010, Jeff Garzik published a patch that immediately increases the block size to 7MB.[8] The patch had no users, but it was the earliest attempt at increasing the block size through a hardfork. Satoshi and theymos immediately said not to implement it, as it would make the user's node incompatible with the network.[9] This is the oft-cited post which many people claim proves Satoshi intended for the blocksize to increase. English, however, does not work that way. Satoshi spoke conditionally, not intentionally.[9]

Positions below are based on a suggested fixed block size increase to 20MiB. Positions against these larger blocks do not necessarily imply that they are against an increase in general, and may instead support a smaller and/or gradual increase.