Mimir Store Gateway Error — Quick Fix

In this tutorial, you'll learn about Mimir Store Gateway Error. We cover key concepts, practical examples, and best practices.

The Problem

The Mimir store gateway is unable to serve blocks from object storage. Queries may fail or return incomplete results. The store gateway may have lost connectivity to the bucket or encountered corrupted block metadata.

Error example:

store-gateway: failed to read block: object not found in bucket
store-gateway: unable to sync blocks: permissions error
store-gateway: query error: block meta.json corrupted

The Fix

Step 1: Check bucket access

WRONG — restarting the store gateway without checking the bucket:

# The store gateway will fail again if the bucket is inaccessible

RIGHT — verify object storage access:

# Test S3 bucket access (example for AWS S3)
aws s3 ls s3://mimir-blocks/

# From inside the store gateway pod
kubectl exec -n mimir mimir-store-gateway-0 -- \
  python3 -c "import boto3; s3 = boto3.client('s3'); s3.head_bucket(Bucket='mimir-blocks')"

Step 2: Force block re-sync

WRONG — manually deleting block metadata files:

# The store gateway should handle re-sync on its own

RIGHT — trigger a resync:

# In Mimir config
blocks_storage:
  bucket_store:
    sync_dir: /data/blocks-cache
    bucket_index:
      enabled: true
      update_on_error: true

Restart the store gateway to trigger a fresh bucket index download:

kubectl rollout restart statefulset/mimir-store-gateway -n mimir

Use DodaTech's Mimir Store Gateway Monitor to track block syncing, cache hit rates, and bucket connectivity across all store gateway instances.

Prevention Tips

• Use dedicated service accounts with minimal bucket permissions (read-only)
• Configure bucket_index: enabled: true for faster startup and sync
• Monitor cortex_bucket_store_block_loads_total and error rates
• Set appropriate block sync intervals for large buckets
• Use DodaTech's Mimir Storage Audit Tool for periodic block integrity checks

Common Mistakes with store gateway

1. Overlapping type class instances that cause GHC to reject the program with ambiguous dispatch errors
2. Non-exhaustive pattern matches that compile with warnings then crash at runtime
3. Misunderstanding that String is [Char] with poor performance for large text operations

These mistakes appear frequently in real-world MIMIR code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ

Related: DodaTech's Mimir Operations Guide provides best practices for store gateway scaling, bucket index configuration, and block lifecycle management.