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Training Checkpoint Corruption on Write

Training checkpoint corruption on write happens when storage failures, power loss, or process kills interrupt the write operation.

Quick answer

Training checkpoint corruption on write happens when storage failures, power loss, or process kills interrupt the write operation.

Reliability#checkpoint#corruption#write#atomic#reliability#storage

What this failure is

Training Checkpoint Corruption on Write is a Reliability failure seen during ML training runs. Training checkpoint corruption on write happens when storage failures, power loss, or process kills interrupt the write operation. Common tags: Checkpoint, Corruption, Write, Atomic.

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Why it happens (the mechanism)

Process killed during checkpoint write (SIGKILL, OOM). Storage failure during write. Network interruption when writing to network storage. Concurrent writes to same checkpoint file. Taken together, these mechanisms explain why the failure is reproducible, why it tends to surface on specific workloads or scales, and why generic mitigation attempts often fall short without addressing the underlying cause.

What you'll observe

  • Checkpoint file is corrupted after save
  • Checkpoint size is smaller than expected
  • Loading checkpoint fails after training run

Common symptoms and what they mean

SymptomWhy it happens
Checkpoint file is 0 bytes or truncatedProcess killed during checkpoint write (SIGKILL, OOM)
UnpicklingError or OSError when loading checkpointStorage failure during write
Checkpoint was being written when process was killedNetwork interruption when writing to network storage

Which systems are affected

  • Long-running training with frequent checkpoints
  • Training on preemptible instances
  • Training on NFS or cloud storage

How to confirm this is the problem

Use this checklist to test the hypothesis against a small reproduction. No single line proves the root cause, so preserve the preceding events and compare one variable at a time.

  • ✓Reproduce the failure from a clean checkpoint/seed: the symptom must appear without warm-up state from a previous run.
  • ✓Verified signal present: Checkpoint file is 0 bytes or truncated
  • ✓Verified signal present: UnpicklingError or OSError when loading checkpoint
  • ✓Verified signal present: Checkpoint was being written when process was killed
  • ✓A targeted fix from the "How to fix it" section eliminates or substantially reduces the symptom within one validation pass.

The fix and the prevention pattern

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Related failures to investigate next

Bytedance Sequence Length Straggler often co-occurs with this failure because both share underlying assumptions about reliability; if you fix this entry but still see drift, validate the related primary cause next. bytedance sequence length straggler →
Nfs Mount Failure often co-occurs with this failure because both share underlying assumptions about reliability; if you fix this entry but still see drift, validate the related neighboring cause next. nfs mount failure →
Checkpoint Partial Save often co-occurs with this failure because both share underlying assumptions about reliability; if you fix this entry but still see drift, validate the related neighboring cause next. checkpoint partial save →

Root cause

  • Process killed during checkpoint write (SIGKILL, OOM)
  • Storage failure during write
  • Network interruption when writing to network storage
  • Concurrent writes to same checkpoint file

The fix and how to prevent it

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References

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