microsoft/garnet · error · Exception

LogDir specified without enabling tiered storage (UseStorage

Error message

LogDir specified without enabling tiered storage (UseStorage)

What it means

LogDir specifies the on-disk directory for tiered (hybrid-log) records. If LogDir is set but storage tiering is disabled, GetSettings treats it as a contradictory config and throws, because without tiering the store uses a NullDevice and the directory would never be used. The message references the legacy flag name UseStorage.

Source

Thrown at libs/server/Servers/GarnetServerOptions.cs:809

                    logger?.LogInformation("[Store] No Read cache log memory size limit will be enforced");
                }
            }

            if (EnableStorageTier)
            {
                if (LogDir is null or "")
                    LogDir = Directory.GetCurrentDirectory();
                logFactory = GetInitializedDeviceFactory(LogDir);

                // These must match GetInitializedSegmentFileDevice.GetStoreHLogDevice
                kvSettings.LogDevice = logFactory.Get(new FileDescriptor("Store", "hlog"));
                if (!DisableObjects)
                    kvSettings.ObjectLogDevice = logFactory.Get(new FileDescriptor("Store", "hlog_objs"));
            }
            else
            {
                if (LogDir != null)
                    throw new Exception("LogDir specified without enabling tiered storage (UseStorage)");
                kvSettings.LogDevice = new NullDevice();
                logFactory = null;
            }

            if (CopyReadsToTail)
                kvSettings.ReadCopyOptions = new(ReadCopyFrom.AllImmutable, ReadCopyTo.MainLog);

            if (RevivInChainOnly)
            {
                logger?.LogInformation("[Store] Using Revivification in-chain only");
                kvSettings.RevivificationSettings = RevivificationSettings.InChainOnly.Clone();
            }
            else if (UseRevivBinsPowerOf2)
            {
                logger?.LogInformation("[Store] Using Revivification with power-of-2 bins");
                kvSettings.RevivificationSettings = RevivificationSettings.PowerOf2Bins.Clone();
                kvSettings.RevivificationSettings.NumberOfBinsToSearch = RevivNumberOfBinsToSearch;
                kvSettings.RevivificationSettings.RevivifiableFraction = RevivifiableFraction;

View on GitHub (pinned to 951b0fc683)

Solutions

1. Enable storage tiering so LogDir is honored: add --storage-tier.
2. If you truly want an in-memory-only store (NullDevice), remove --logdir.
3. Review the config so LogDir and --storage-tier are always paired.

Example fix

# before (fails)
garnet-server --logdir /data/garnet

# after
garnet-server --storage-tier --logdir /data/garnet

if (!options.EnableStorageTier && !string.IsNullOrEmpty(options.LogDir)) {
    throw new InvalidOperationException("LogDir requires EnableStorageTier (--storage-tier)");
}

When it happens

Trigger: Starting with --logdir/-l set but --storage-tier not enabled. Thrown at GarnetServerOptions.cs:808-809 (the else-branch taken when EnableStorageTier is false).

Common situations: Setting a log directory intending to persist data while forgetting to enable the storage tier; stale config from a version where tiering was implied; misunderstanding that LogDir alone does not enable persistence.

Related errors

• MutablePercent must be between 10 and 95
• Store Log Memory size or PageCount must be specified
• Index size {IndexMemorySize} should not be less than index m
• Read cache requires storage tiering to be enabled
• Read Cache Log Memory size or PageCount must be specified

AI-assisted analysis of microsoft/garnet@951b0fc683 (2026-08-13). Data as JSON: /api/errors/71e0ba860b02fb1a. Report an issue: GitHub.