Arbitrum Halts Transaction Processing for One Hour
On August 19, Offchain Labs, the team behind the Ethereum layer-2 solution Arbitrum, disclosed that the network experienced a temporary halt on August 18.
Arbitrum Halts Transaction Processing for One Hour
According to data from Arbiscan, Arbitrum encountered a period of inactivity on August 18, spanning one hour between batches 316.002 and 316.003. During this dark period, many users reported the network's inability to process transactions, leading to speculation that the entire blockchain might have been frozen or non-functional.
The issue was pinpointed to batches 316.002 and 316.003. Source: Arbiscan
Shortly after, CTO Harry Kalodner confirmed the incident and provided an explanation via his personal Twitter account.
1/ Was Arbitrum One down for an hour? No
— Harry Kalodner (💙,💙) (@hkalodner) August 18, 2023
Did the batch poster stop posting for an hour? Yes
What does this all mean? 🧵
Kalodner attributed the disruption to "batch posters." While batch posters ceased to submit transaction batches, the sequencer continued to accept and sequence transactions, as well as confirm them. For most users, the chain operated normally, but final transactions were unsuccessful.
The CTO further analyzed that the batch posters encountered a rare case in processing geth's mempool, resulting in transaction rejections if the total fees of all transactions in the mempool exceeded the sender's balance. This prevented batch posters from increasing fees for any transactions. Complicating matters, the ETH balance of Arbitrum One's batch poster was stored in a separate smart contract called gas refunder, designed to refund ETH spent on posting, enhancing its security fund.
Although the batch poster had enough ETH to submit all transactions, it was rejected by geth. Is geth itself to blame? Possibly, but not entirely. The batch poster consumed about 2% of Ethereum's gas limit, and the gas refunder functioned differently. Such incidents are inevitable.
As of now, the issue has been completely resolved, and the network is processing transactions smoothly.
The incident has been resolved, Arbitrum continuously processes transactions on-chain, data from Arbiscan
However, this is not the first time this layer-2 solution has encountered issues. Earlier in June this year, Arbitrum suffered from sequencer errors that caused the network to halt transaction processing for several hours.
