Polygon zkEVM 中斷：深入揭示以太坊重組和同步問題

Polygon 的zkEVM 網路因故障導致區塊生產停止了14 個小時，一周多後，開發人員發布了一份事後分析報告，解釋以太坊主網重組導致排序器接受帶有已棄用時間戳的交易，從而導致了故障。

Polygon zkEVM Outage: Deep Dive into the Causes and Mitigation Measures

Polygon zkEVM 中斷：深入探討原因與緩和措施

Over a week ago, Polygon Labs' Ethereum Layer 2 solution, Polygon zkEVM, experienced an unexpected outage that halted block production on the network for several hours. While the issue has since been resolved, the specific causes of the disruption remained shrouded in uncertainty until now. In a comprehensive post-mortem report, developers have shed light on the root causes of the event and outlined proactive steps taken to prevent future occurrences.

一週多前，Polygon Labs 的以太坊第 2 層解決方案 Polygon zkEVM 經歷了意外中斷，導致網路上的區塊生產停止了幾個小時。儘管該問題已解決，但造成中斷的具體原因至今仍存在不確定性。在一份全面的事後分析報告中，開發人員闡明了該事件的根本原因，並概述了為防止未來再次發生而採取的積極措施。

Unraveling the Ethereum Reorg Trigger

揭開以太坊重組觸發器的面紗

In their initial statements, Polygon Labs attributed the Polygon zkEVM outage to an Ethereum mainnet "reorg." A reorg, short for reorganization, occurs when a consensus disagreement over transaction ordering or validity arises, forcing the network to converge on a single version of the blockchain history, prioritizing the chain with the most computational work or stake backing it.

在最初的聲明中，Polygon Labs 將 Polygon zkEVM 中斷歸因於以太坊主網「重組」。當對交易順序或有效性出現共識分歧時，就會發生重組，迫使網路收斂於區塊鏈歷史的單一版本，優先考慮具有最多計算工作或支持它的權益的鏈。

According to the developers' post-mortem analysis, the Ethereum reorg in this instance resulted in the omission of a Polygon zkEVM deposit transaction. This critical change was not detected promptly by the Layer 2 chain's synchronizer, a component responsible for monitoring and relaying Layer 1 changes to Layer 2.

根據開發人員的事後分析，這次以太坊重組導致 Polygon zkEVM 存款交易被遺漏。第 2 層鏈的同步器（負責監控第 1 層變更並將其中繼到第 2 層的組件）未能及時偵測到此關鍵變更。

Synchronization Failure and Transaction Rejection

同步失敗和事務拒絕

The synchronizer's lapse in detecting the omitted deposit transaction had a cascading effect on the Polygon zkEVM sequencer, the component responsible for ordering and batching transactions for posting to the Ethereum mainnet. Unaware of the updated mainnet state, the sequencer continued to order transactions with timestamps that had become outdated on the mainnet.

同步器未能偵測到遺漏的存款交易，這對 Polygon zkEVM 排序器（負責排序和大量交易以發佈到以太坊主網的元件）產生了連鎖效應。排序器不知道更新的主網狀態，繼續使用主網上已過時的時間戳記對交易進行排序。

As a result, when these transactions were batched to the mainnet, they were rejected by the network due to their invalid timestamps. "Valid proofs for these transactions were generated, but the result of these transactions were no-operation, as if they were not there," the developers explained.

結果，當這些交易被批量發送到主網時，由於時間戳無效而被網路拒絕。 「這些交易的有效證明已經生成，但這些交易的結果是空操作，就好像它們不存在一樣，」開發人員解釋道。

Impact and Remediation

影響和補救

Approximately 4,000 transactions were affected by the outage. The developers attributed the prolonged 14-hour downtime to the efforts required to reconcile these affected transactions.

大約 4,000 筆交易受到中斷影響。開發人員將長達 14 小時的停機時間歸因於協調這些受影響的交易所需的努力。

In response to the incident, developers have released updated versions of the zkEVM node and prover components, including enhancements to the synchronizer to improve its ability to detect and respond to Layer 1 changes. Additionally, they have implemented an extra safeguard in the sequencer to cross-check transaction timestamps with the mainnet before batching them for submission.

為了應對這一事件，開發人員發布了 zkEVM 節點和證明者元件的更新版本，包括對同步器的增強，以提高其偵測和回應第 1 層變更的能力。此外，他們在排序器中實施了額外的保護措施，以便在批量提交之前與主網交叉檢查交易時間戳。

TVL Resilient, but Some Transactions May Require Further Attention

TVL 有彈性，但某些交易可能需要進一步關注

Polygon zkEVM's total value locked (TVL) appears to have remained largely unaffected by the outage. At the time of writing, L2Beat data indicates a slight increase from approximately $150 million to $153 million since the incident.

Polygon zkEVM 的總鎖定值 (TVL) 似乎基本上沒有受到中斷的影響。截至撰寫本文時，L2Beat 數據顯示，自事件發生以來，銷售額從約 1.5 億美元略有增加至 1.53 億美元。

However, Polygon Labs has cautioned that some of the affected transactions may still be pending processing. DApps that have identified affected transactions are encouraged to reach out to Polygon Labs for assistance.

然而，Polygon Labs 警告稱，一些受影響的交易可能仍在等待處理。我們鼓勵已發現受影響交易的 DApp 聯繫 Polygon Labs 尋求協助。

Contextualizing the Outage

停電的具體情況

The Polygon zkEVM outage highlights the growing prevalence of network disruptions in the cryptocurrency space, particularly in the Ethereum Layer 2 ecosystem. In December 2023, Arbitrum, the largest Ethereum Layer 2 network by TVL, experienced an outage lasting over five hours due to a surge in network activity. Similarly, zkSync Era, the largest ZK-rollup by TVL, faced a four-hour outage in the same month.

Polygon zkEVM 中斷凸顯了加密貨幣領域網路中斷日益普遍，特別是在以太坊第 2 層生態系統。 2023 年 12 月，TVL 最大的以太坊第 2 層網路 Arbitrum 由於網路活動激增而經歷了長達五個多小時的中斷。同樣，TVL 最大的 ZK-rollup zkSync Era 在同月也面臨四小時的宕機。

Importance of Post-Mortem Analysis

事後分析的重要性

This post-mortem report provides valuable insights into the causes and resolution of the Polygon zkEVM outage, addressing lingering uncertainties surrounding the incident. It underscores the importance of post-mortem analyses in enhancing the understanding of network disruptions, identifying areas for improvement, and building more resilient systems.

這份事後分析報告提供了有關 Polygon zkEVM 中斷的原因和解決方案的寶貴見解，解決了圍繞該事件的揮之不去的不確定性。它強調了事後分析在增強對網路中斷​​的理解、確定需要改進的領域以及建立更具彈性的系統方面的重要性。