IOTA was unable to process transactions for 15 hours due to a bug with its “Coordinator,” a centralized node which determines which transactions are confirmed.
Bug Stops IOTA Transactions
On Dec. 29 around 11 a.m. the IOTA Tangle stopped processing transactions. The bug was identified and fixed 15 hours after the stoppage, as first reported by The Block. During the outage, the system could still transfer data and users could still read transactions.
David Sønstebø, IOTA’s co-founder, described the bug as “minor.” The issue will be addressed when the project moves away from using the Coordinator, in an upgrade known as Coordicide, he added.
“Whatever the bug is, there is no reason to panic over such a minor issue pre-Coordicide. This is precisely why Coordicide takes time, one can’t execute it until all possible kinks have been ironed out.”
IOTA’s leadership was heavily criticized by the crypto community for classifying the issue as minor.
Untangling IOTA’s System
Unlike other systems, IOTA uses a directed-acyclic graph, or DAG, rather than a blockchain. This system presents unique challenges and potential, though still experimental, advantages over a blockchain. Instead of mining or staking, transactions are validated by confirmation from at least two other transactions.
However, for these transactions to get properly validated a centralized node controlled by the IOTA Foundation, known as the Coordinator, is necessary. Further development is needed for a DAG to work without such a bottleneck.
According to the bug fix, the IOTA Reference Implementation “didn’t account for a transaction that was shared between two distinct bundles. Once it marked it as ‘counted’ in one bundle, it was ignored for the next bundle. This lead to a corrupt ledger state.”
Regardless of the reason behind the issue, the stoppage highlights centralization and reliability issues the IOTA Foundation must address before it’s ready for meaningful adoption.