Failed to create bucket

Error message

Failed to create bucket %s: %s, previous error: %s
Please create bucket %s manually, then format again.

What it means

The initial Put failed with a NoSuchBucket error, and the automatic bucket-creation attempt (store.Create) also failed. JuiceFS tried to create the missing bucket for you but could not, and it instructs you to create the bucket manually before formatting again.

Solutions

Create the bucket manually with the provider CLI: `aws s3 mb s3://mybucket --region us-east-1`
Correct the bucket name and endpoint in the --storage-url / format options
Grant s3:CreateBucket permission if the bucket should be auto-created
Verify the region: a bucket created in us-west-2 cannot be used via a us-east-1 endpoint in some providers

Example fix

// before
juicefs format ... s3://mybucket
// Failed to create bucket...
// after
aws s3 mb s3://mybucket --region us-east-1
juicefs format ... s3://mybucket

Defensive patterns

Strategy: validation

Validate before calling

// pre-check bucket existence
// aws s3api head-bucket --bucket mybucket || aws s3 mb s3://mybucket

Type guard

func isNoSuchBucket(err error) bool {
    return err != nil && strings.Contains(err.Error(), "NoSuchBucket")
}

Try / catch

err := doTesting(ctx, store, key, data)
if err != nil && strings.Contains(err.Error(), "Please create bucket") {
    // create bucket manually, then re-run format
}

Prevention

Create the bucket before running juicefs format
Double-check bucket name spelling and region in the storage URL
Grant s3:CreateBucket if auto-creation is desired
Match the endpoint to the bucket's region

When it happens

Trigger: `juicefs format` with a bucket name/endpoint that doesn't exist, where the credentials also lack s3:CreateBucket permission, region is wrong (creation against wrong region endpoint), or the provider does not support auto-creation (e.g. some S3-compatible stores).

Common situations: Typo in bucket name; AWS account at a different region than the endpoint; IAM user with object permissions but not bucket-management permissions; OSS/COS endpoints mismatching the bucket region.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

AI-assisted analysis of juicedata/juicefs@c9a67b23e8 (2026-09-06). Data as JSON: /api/errors/272b03d6a6a29263. Report an issue: GitHub.

Appendix: source

Thrown at cmd/format.go:341

var letters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")

func randSeq(n int) string {
	b := make([]rune, n)
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	for i := range b {
		b[i] = letters[r.Intn(len(letters))]
	}
	return string(b)
}

func doTesting(ctx context.Context, store object.ObjectStorage, key string, data []byte) error {
	if err := store.Put(ctx, key, bytes.NewReader(data)); err != nil {
		if strings.Contains(strings.ToLower(err.Error()), "denied") {
			return fmt.Errorf("Failed to put: %s", err)
		}
		if err2 := store.Create(ctx); err2 != nil {
			if strings.Contains(err.Error(), "NoSuchBucket") {
				return fmt.Errorf("Failed to create bucket %s: %s, previous error: %s\nPlease create bucket %s manually, then format again.",
					store, err2, err, store)
			} else {
				return fmt.Errorf("Failed to create bucket %s: %s, previous error: %s",
					store, err2, err)
			}
		}
		if err := store.Put(ctx, key, bytes.NewReader(data)); err != nil {
			return fmt.Errorf("Failed to put: %s", err)
		}
	}
	// GLACIER storage class doesn't allow read after write
	if _, ok := ctx.Value(object.TierKey{}).(uint8); ok {
		return nil
	}
	p, err := store.Get(ctx, key, 0, -1)
	if err != nil {
		return fmt.Errorf("Failed to get: %s", err)
	}

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