1 DELETE for Named Objects
- 1.1 Guidelines for DELETE
- 1.2 DELETE for Domains and Buckets
- 1.3 Reusing Bucket Names
2 DELETE for Unnamed Objects
3 DELETE for alias Objects

This section provides general information about SCSP DELETE that applies to both named and unnamed objects.

DELETE is a request to the storage cluster to remove a specific object. The DELETE request is formatted as an HTTP request using the DELETE method.

SCSP Method	HTTP Method	RFC 7231 Section

SCSP Method	HTTP Method	RFC 7231 Section
SCSP DELETE	DELETE	4.3.5

DELETE for Named Objects

DELETE /bucket/photo.jpg HTTP/1.1
  Host: cluster.example.com
  User-Agent: Swarm Client/0.1

Guidelines for DELETE

For bucket requests, use a separate initialization or setup routine that runs less frequently. Swarm is optimized for calls on individual objects, not domains or buckets (which are centralized resources), so do not make bucket calls on the high-availability code path of a client application.
Reuse object names. After a named object is deleted, another object with the same name can be created in the same bucket. Unlike unnamed objects, whose UUIDs are not reused, names can be reused.
Pause before recreating. Deleting a named object involves an underlying update, for Swarm to write a special marker value to the name. When recreating a named object after deleting it, wait at least one second.

DELETE for Domains and Buckets

Delete any objects contained within a domain or bucket when deleting them or else these objects are orphaned, lost, and consume disk space unnecessarily. These deletes are recursive, iterating until every object contained in the domain or bucket is dealt with.

Note

Swarm generates an SCSP error if attempting to delete a domain or bucket without having a recursive argument or parameter in force.

The recursive query argument must be included to delete a domain or bucket:

recursive | recursive=true|yes
- Grants a 1-week grace period (default) during which the domain or bucket can be restored before the health processor begins reclaiming the space.
- Edit the health.recursiveDeleteDelay parameter to change the length of the grace period
recursive=now
- Grants no grace period. The health processor begins reclaiming the space immediately.

Avoid changing the recursive argument if existing integrations do not use the argument. Add a global configuration parameter: scsp.autoRecursiveDelete=True.

An erroneously deleted domain or bucket can be restored without data loss if it is within the grace period. See https://perifery.atlassian.net/wiki/spaces/public/pages/2443811433.

Reusing Bucket Names

A bucket can be deleted and another bucket with the same name can be recreated:

The new bucket is a different bucket that happens to have the same name.
All objects in a bucket are inaccessible after deleting it, even if another bucket with the same name is subsequently created.

Best Practice

Wait at least twice the value of cache.realmStaleTimeout before attempting to recreate a bucket with the same name as a bucket deleted: the default is 600 seconds (10 minutes), so wait 20 minutes, then create the new bucket. This waiting period applies to reusing names of buckets: deleting a named object and recreating an object with that name requires a 1-second pause.

DELETE for Unnamed Objects

DELETE /7A25E6067904EAC8002498CF1AE33023 HTTP/1.1
  User-Agent: Swarm Client/0.1

Error

Error loading excerpt from "WRITE for Unnamed Objects".

The content associated with the name or UUID supplied in the request is no longer available if the method succeeds. This does not imply all copies of the content are erased. The cluster now responds to any READ request for that UUID with an HTTP 404 Not Found error.

An object can be deleted by an application or lifecycle as follows:

Application deleting an object - All online replicas in a single cluster are removed immediately after a delete method is executed on an object. (An online replica is one that resides on a cluster node online at the time the delete is issued.) The cluster recalls the name or UUID has been deleted for 14 days, in the event that one or more nodes holding replicas of the deleted object are off line at the time the delete was issued.
Policy deleting an object - An object can have a storage policy defined by the application and stored along with it. Part of the storage policy may be an expiration period, beyond which the object is to be removed. In the case of a policy-defined deletion, all replicas, wherever they are stored, are deleted at approximately the same time and become unavailable at most one second after the expiration date and time.

DELETE for alias Objects

To delete alias objects, add a query argument alias:

DELETE /7A25E6067904EAC8002498CF1AE33023?alias HTTP/1.1
  User-Agent: Swarm Client/0.1