HTTP 507 Insufficient Storage
HTTP 507 Insufficient Storage is a server-error status from RFC 4918 (WebDAV). It means the method could not be performed because the server is unable to store the representation needed to complete the request — for example a write that would exceed available disk space or a storage quota. It is a 5xx, so crawlers treat the URL as temporarily failing.
What this means
507 Insufficient Storage is defined in RFC 4918, the WebDAV specification, but the concept generalises: the server could not complete the request because it cannot store the representation required. The classic trigger is a write (PUT, or a WebDAV operation) that would exceed available disk or an allocated quota.
Because it is a 5xx server error, a compliant client should treat the request as having failed on the server side, not because of anything wrong with the request itself.
Common causes and fixes
507s usually mean an origin or upload backend has run out of space, hit a per-account quota, or cannot allocate temporary storage to build the response. On read-heavy content sites a 507 is uncommon, so its appearance often points to an upload service, a cache that writes to disk, or a logging/temp directory that filled.
Resolution is operational: free or expand storage, raise or correct quotas, and add monitoring so capacity is addressed before requests start failing. For crawlers, sustained 507s on indexable URLs risk those pages being seen as repeatedly unavailable.
- RFC 4918 server error: cannot store the required representation
- Common triggers: full disk, exceeded quota, temp-storage exhaustion
- Operational fix: free/expand storage, correct quotas, add monitoring
How it appears in analytics and logs
A 507 means the server could not store what the request required. As a 5xx it signals a server-side failure; for crawlers it is a transient error, but recurring 507s point to a real capacity or quota problem on the origin.
Diagnostic use case
Diagnose write or upload failures where the server returns 507 because it has run out of storage or hit a quota, distinct from a generic 500.
What WebmasterID can help detect
WebmasterID records the status returned to crawler fetches, so a rise in 507 responses surfaces in bot-intelligence as a storage/capacity failure rather than a content issue, separate from human analytics.
Common mistakes
- Returning a generic 500 for storage exhaustion instead of the specific 507.
- Ignoring intermittent 507s until storage fully fails and pages go down.
- Letting temp or log directories fill and cause 507s on unrelated requests.
Privacy and accuracy notes
A 507 is a server-capacity response with no visitor identity attached. WebmasterID records crawler fetch statuses without linking them to a person.
Related pages
- HTTP 500 and crawl health
500 Internal Server Error is a generic message that something went wrong on the server and it could not complete the request. Occasional 500s happen, but repeated 500s on important URLs harm crawl health: crawlers may slow down and, if errors persist, treat affected pages as unreliable.
- HTTP 503 Service Unavailable for maintenance
503 Service Unavailable means the server is temporarily unable to handle the request, usually due to maintenance or overload. It is the correct, index-protecting status for planned downtime: with a Retry-After header, compliant crawlers understand the outage is temporary and come back later.
- Monitoring crawl errors over time
Monitoring crawl errors means watching, over time, the rate and type of failures crawlers encounter: rising 404s, new 5xx spikes, redirect chains, robots.txt fetch failures, and host-status problems. Caught early through Search Console reports, server logs, and uptime checks, these are cheap to fix; caught late, after pages drop from the index, they are costly. The goal is trend detection, not one-off checks.
- Website observability
Catch storage-error status codes like 507 returned to crawlers, server-side.
Sources and verification notes
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.