sgl-project/sglang · error · ValueError

extra_config['ssd_durability_mode'] must be one of: strict,

Error message

extra_config['ssd_durability_mode'] must be one of: strict, sync, relaxed, async

What it means

extra_config['ssd_durability_mode'] must be one of strict, sync, relaxed, async. Validation happens even if the UMBPDurabilityMode enum is unavailable (older mori or mocks), so invalid values always fail fast.

Source

Thrown at python/sglang/srt/mem_cache/storage/umbp/umbp_store.py:351

        if "eviction_policy" in extra:
            cfg.eviction.policy = str(extra["eviction_policy"])
        if "eviction_candidate_window" in extra:
            cfg.eviction.candidate_window = int(extra["eviction_candidate_window"])
        if "ssd_io_backend" in extra:
            backend = str(extra["ssd_io_backend"]).strip().lower()
            if backend not in ("posix", "io_uring"):
                raise ValueError(
                    "extra_config['ssd_io_backend'] must be one of: posix, io_uring"
                )
            if UMBPIoBackend is not None:
                cfg.ssd.io.backend = (
                    UMBPIoBackend.Posix if backend == "posix" else UMBPIoBackend.IoUring
                )
        if "ssd_durability_mode" in extra:
            # Validate even when the enum is unavailable (older mori / mocks).
            durability = str(extra["ssd_durability_mode"]).strip().lower()
            if durability not in ("strict", "sync", "relaxed", "async"):
                raise ValueError(
                    "extra_config['ssd_durability_mode'] must be one of: "
                    "strict, sync, relaxed, async"
                )
            if UMBPDurabilityMode is not None:
                if durability in ("strict", "sync"):
                    cfg.ssd.durability.mode = UMBPDurabilityMode.Strict
                else:
                    cfg.ssd.durability.mode = UMBPDurabilityMode.Relaxed
        if "ssd_backend" in extra:
            ssd_backend = str(extra["ssd_backend"]).strip().lower()
            if ssd_backend not in ("file", "spdk", "spdk_proxy"):
                raise ValueError(
                    "extra_config['ssd_backend'] must be one of: "
                    "file, spdk, spdk_proxy"
                )
            cfg.ssd.ssd_backend = ssd_backend
        if "spdk_nvme_pci_addr" in extra:
            cfg.ssd.spdk_nvme_pci_addr = str(extra["spdk_nvme_pci_addr"])

View on GitHub (pinned to 0132848349)

Solutions

1. Use one of: strict, sync, relaxed, async (case-insensitive)
2. Pick strict/sync for crash safety, relaxed/async for throughput as appropriate

Example fix

# before
extra['ssd_durability_mode'] = 'fsync'
# after
extra['ssd_durability_mode'] = 'strict'

assert str(extra.get('ssd_durability_mode','')).strip().lower() in ('strict','sync','relaxed','async')

def is_valid_durability(v) -> bool:
    return isinstance(v, str) and v.strip().lower() in ('strict','sync','relaxed','async')

When it happens

Trigger: Setting ssd_durability_mode to an unrecognized string like 'fsync', 'none', or 'async_strict' in extra_config.

Common situations: Guessing durability names; carrying over config from a different store version where names differed.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• extra_config[{!r}] must be a boolean-like value (true/false,
• {} must not be None
• {} must not be empty
• {} has {} entries, but rank_index={}
• extra_config['ssd_io_backend'] must be one of: posix, io_uri

AI-assisted analysis of sgl-project/sglang@0132848349 (2026-08-28). Data as JSON: /api/errors/f0678acc3a27b990. Report an issue: GitHub.