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さくら高火力サービスにおけるH100 NDR/RoCE NCCLタイムアウトの自動診断

Mellanox ConnectX-7アダプタのQP枯渇、ノード間テナント接続の不整合、および16bit学習時のPCIe AER内部エラーを特定します。

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さくら高火力のマルチノード障害ログを再生

Upload your log file. Review the selected evidence and masking, then run diagnosis. Keep the original log for any follow-up questions.

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training_logs.txt

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Upload your log file. Large files are processed in your browser. Only selected evidence is submitted when you run diagnosis.

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What a useful evaluation should establish

待機中の正常なGPUノードを誤って再起動することなく、根本原因となった劣化したHCAポートまたはリンク障害を正確に特定します。

Use Denpex alongside your existing telemetry tools to investigate submitted incident evidence. With monitoring configured on a supported plan, detected failures can trigger alerts and an automatic diagnosis from the captured evidence.

Inside Denpex

See the evidence, not just the claim

Follow the causal chain, inspect the quoted evidence and prepare the next handoff. These actual product captures use founder-account examples and the VS Code extension, with the source identified under each image. Open a capture to inspect it at full size.

Denpex founder-account example: a causal graph connects an Xid 48 ECC event to a rank exit and downstream collective failures, with quoted evidence for each stage. — Live founder-account capture from the bundled NCCL/ECC example. Follow the hardware event, rank exit and downstream symptoms with a supporting log quote at each stage.Inspect original image

Denpex hardware handoff summary asks the operator to capture diagnostic evidence and verify RMA eligibility with the vendor. — Actual hardware handoff summary from the same founder-account example. Capture diagnostic evidence before an approved reset, then confirm RMA eligibility with the vendor.Inspect original image

Denpex historical example says a collective timeout does not establish the initiating rank, cause or failure domain and requests distinguishing evidence before a remedy. — Founder-account example restored from history. The original timeout remains unattributed, and the UI keeps the missing-evidence assessment visible.Inspect original image

Denpex VS Code extension displaying a bundled OOM-before-NCCL example, matched log evidence, verification guidance and an investigation handoff. — Actual VS Code extension capture of the bundled OOM-before-NCCL example. Review matched log evidence, verification guidance and the investigation handoff without leaving the editor.Inspect original image

Failure Signature Triage

さくらインターネット高火力 - Observed Runtime Evidence

さくらインターネット高火力公式ドキュメント

Incident pattern summary

さくらインターネット高火力のH100ノード間で実行される分散学習が、最初のAllReduceステップで停止。NCCL_IB_HCAインターフェースバインドの不整合とRoCEパケットドロップを特定し、ハードウェア故障と設定不整合を正確に切り分けます。

Terminal traceback excerpt (さくらインターネット高火力)

[rank 3]:[../../../../../../csrc/distributed/ProcessGroupNCCL.cpp:732] [Rank 3] Watchdog caught collective operation timeout: WorkState::InProgress, opType: 1 (ALLREDUCE), p2p: 0, timeout (sec): 60
[E 2026-10-28 01:14:22.091422 3421107] NCCL WARN Connect to [10.100.4.12:15432]: Transport endpoint is not connected
[FATAL] NCCL error: unhandled system error / cma failure in ibv_poll_cq