What Is a 507 Status Code?
The 507 Insufficient Storage HTTP status code indicates that the server cannot complete the request because it does not have enough free storage to store the representation required. This is not a failure of the request itself, but a limitation in the server’s current capacity.
Defined in RFC4918 Section 11.5, the 507 status code is part of the WebDAV (Web Distributed Authoring and Versioning) extension of HTTP. It is specifically designed to handle file management operations, such as uploading large files, syncing, or storing versioned documents.
This error is a server-side condition and considered temporary—meaning it might be resolved later once space becomes available. However, the request must not be automatically retried by the client, unless prompted again through a distinct user action.
Why It Happens:
The 507 error occurs when the server:
Runs out of disk space
Exceeds a quota set for a specific user, directory, or service
Encounters storage system errors such as write failures or degraded file systems
It is specific and diagnostic, meaning the server explicitly reports its inability to fulfill the request due to capacity limitations.
When You’re Likely to See a 507 Error:
Uploading large files (e.g., via PUT or POST methods)
Performing batch writes or backups to a constrained server
Using WebDAV-based clients that sync directories across devices
Deploying applications to a server without verifying storage availability
The 507 Insufficient Storage status code is a clear signal that the request is valid, but the server cannot process it at that moment due to a lack of physical or quota-based storage. Unlike a 500 or 503 error, which may reflect general failure or overload, 507 is specific to space-related capacity issues.
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507 CODE REFERENCES
507 CODE REFERENCES
The 507 Insufficient Storage status code, while not as commonly encountered as others in the 5xx series, is formally recognized and supported in a number of modern programming languages and frameworks—especially those with WebDAV or file-handling capabilities. Here’s how the 507 status code is referenced across various ecosystems:
Common Language & Framework Constants
| Environment / Framework | 507 Reference Constant |
|---|---|
| Rails (Ruby on Rails) | :insufficient_storage |
| Symfony (PHP) | Response::HTTP_INSUFFICIENT_STORAGE |
| .NET / C# | HttpStatusCode.InsufficientStorage |
| Rust | http::StatusCode::INSUFFICIENT_STORAGE |
| Go | http.StatusInsufficientStorage |
| Python 3.5+ | http.HTTPStatus.INSUFFICIENT_STORAGE |
| Apache HttpComponents | org.apache.hc.core5.http.HttpStatus.SC_INSUFFICIENT_STORAGE |
| Angular | HttpStatusCode.InsufficientStorage |
Notes on Compatibility:
In Python, this constant is only available in Python 3.5 and later as part of the
httpmodule.Node.js does not have a built-in named constant for 507, but you can manually assign it using
res.status(507)or similar patterns in Express.js.Some lower-level libraries may not include 507 by default but allow developers to set custom status codes.
Relevance to WebDAV
The 507 code is part of the WebDAV specification, so you’re more likely to find it handled explicitly in environments or servers that implement:
Document management systems (DMS)
Cloud sync software
Remote file storage interfaces
507 Status Code Example
To better understand how the 507 Insufficient Storage status code works in practice, let’s look at a realistic example involving a file upload operation:
Request
PUT /documents/report.docx HTTP/1.1
Host: example.com
Content-Length: 5000000
Content-Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document
The client attempts to upload a 5MB .docx file to the server. The Content-Length header indicates the file size.
Response
HTTP/1.1 507 Insufficient Storage
Content-Type: text/plain
Content-Length: 42
Server is out of free storage space. 4096MB required
Explanation
In this scenario:
The server is out of disk space or the user has exceeded a storage quota.
It returns
507 Insufficient Storage, making it clear that the failure is due to a temporary lack of storage.The server optionally includes a human-readable message describing the issue and how much space is required to complete the action.
This error acts as a safeguard against failed write operations and is typically encountered in systems dealing with large file uploads or constrained cloud storage environments.
What Causes a 507 Status Code?
The 507 Insufficient Storage status code indicates that the server cannot store the representation needed to complete the request. This is typically due to a temporary storage limitation rather than a permanent configuration issue.
Common Causes:
Disk Space Limit Reached
The most frequent cause is that the server’s disk is full. Whether due to logs, cached files, or other uploads, a saturated disk results in a 507 error.File or User Quotas Exceeded
Some hosting environments enforce quota limits for users or directories. If a user exceeds their allowed storage space, the server will refuse additional data uploads.Storage System Errors
Corrupted partitions, I/O errors, or failed mounting of external drives may simulate a lack of storage even when space is technically available.Virtual or Temporary File Systems
Some environments (e.g., Docker, shared hosting) allocate virtual storage for certain tasks. If the temporary partition is exhausted, 507 errors can be thrown.Cloud-Based Limitations
Platforms like AWS, Azure, or Google Cloud may impose limits on storage buckets or volumes, triggering 507 when exceeded.
How to Fix a 507 Status Code
Resolving a 507 Insufficient Storage error involves addressing server-side limitations. While users may have limited control, developers or administrators can take the following actions:
Troubleshooting Steps
Free Up Disk Space
Identify and remove unnecessary files, logs, or backups occupying space. Use disk analysis tools (e.g.,du,df, or GUI-based tools) to locate large files or directories.Increase Storage Capacity
Expand the disk volume or add additional storage to the server. For cloud services, upgrade the instance’s disk size or attach more persistent storage.Check and Adjust Quotas
For multi-user systems, verify if storage quotas are set. Increase limits for users, groups, or applications that need more space.Review Temporary File Usage
Ensure that temp directories (like/tmp) haven’t filled up. These are often used by servers to stage uploads or cache processes.Clear Application Caches
Content management systems, APIs, or frameworks may accumulate large caches. Clear them safely via admin panels or CLI tools.Implement Alerts and Monitoring
Set up disk usage monitoring and threshold alerts to prevent future 507 errors.
Retry After Fix
Once the storage issue is resolved, the client can retry the request, assuming it hasn’t timed out or been invalidated.
FAQ
What does a 507 status code mean?
A 507 Insufficient Storage status code means the server cannot store the data needed to complete the request. This typically occurs due to limited disk space or user-specific storage quotas. It’s a temporary issue and usually requires server-side intervention.
Is a 507 status code a client or server error?
The 507 status code is a server-side error. It indicates the server doesn’t have enough storage capacity to complete the request. Users can’t fix this themselves—it must be resolved by the server administrator or hosting provider.
How can I fix a 507 Insufficient Storage error?
To fix a 507 error, clear server disk space, expand storage capacity, or adjust storage quotas. If you’re a user encountering this error, contact the website administrator or support team to report the issue.
Does a 507 error affect SEO?
Yes, if search engine bots encounter a 507 error repeatedly, it may impact your site’s indexing and rankings. Regular monitoring and server maintenance can help prevent such crawl errors and maintain search performance.
Can a 507 error be retried automatically?
Generally, 507 errors should not be retried automatically. The HTTP specification states that retries must occur only after a new user action, as the server’s lack of storage must be resolved before another attempt.
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