Home » Dell Manuals » Servers » Dell DX6004S » Manual Viewer

Dell DX6004S DX Object Storage Application Guide - Page 33

Named Object WRITE Details, 3. Unnamed Object WRITE Details, 4. Normal Responses to WRITE

Add to My Manuals
Save this manual to your list of manuals

Page 33 highlights

DX Storage makes no assumptions about User-Agent (except that it is an HTTP/1.1 client). The Host header is mandatory and must conform to the requirements of Section 14.23 of the HTTP/1.1 spec. 6.1.1. About the Expect: 100-continue Header and WRITE The Expect: 100-continue header tells the server that the client will wait after sending just the header lines and before sending the content stream in the body of the message. The DX Storage server can respond with a redirect, an error response, or if it is capable and ready to store the contents, it returns a 100 Continue response, telling the client to proceed with its transmission of the entity body. The client should wait for a 100 Continue response from the server before proceeding to send data. Otherwise, the server might send a 413 (Request entity too large error response) and close the connection. DX Storage allows the client to omit the Expect: 100-continue header, sending all the content data at once, in which case the server reads and discards all data if it must respond with a redirect or error. For WRITEs of more than 65536 bytes, DX Storage logs the following warning if the Expect header is not utilized: Please use Expect: 100-continue for large amounts of data. Additionally, if no node in the cluster has enough space to write the stream, a 507 Insufficient Storage error response is returned. 6.1.2. About Replicate On Write To force a first replication by DX Storage on receipt of the file, set the query argument: replicate=immediate. The value is case-sensitive, and all other values for replicate other than immediate are ignored. If either the replication or the initial write fail, both will fail, and the application returns a 412 error. This feature guarantees that two copies of the stream will be saved on different nodes before returning a 201 Created. 6.2. Named Object WRITE Details In contrast to an unnamed object, if you WRITE a named object that already exists, the existing object is overwritten with a new version. 6.3. Unnamed Object WRITE Details If you WRITE an unversioned stream, a new stream is created and a new UUID is returned. If you WRITE an anchor stream, a new stream is created and a new alias UUID is returned. To create unnamed anchor stream objects, alias=yes is required, as shown in the following example. POST /?alias=yes HTTP/1.1 Host: cluster.example.com User-Agent: DX Storage Client/0.1 6.4. Normal Responses to WRITE For a list of response headers, see Section 4.6, "Normal Response Headers". The following responses can be returned by the DX Storage cluster in the case where the new content stream can be created as requested. The content might be created and written to the cluster by the node to which the request was sent, or it might be redirected to another node in the cluster. HTTP/1.1 201 Created Date: Wed, 1 Sept 2010 15:59:02 GMT Copyright © 2010 Caringo, Inc. All rights reserved 28 Version 5.0 December 2010

Section	Page
DX Object Storage Application Guide	1
Table of Contents	3
Chapter 1. Introduction to DX Storage Objects	6
1.1. Introducing Named Objects	6
1.2. Summary of Named Objects and Unnamed Objects	7
1.3. Common Named Object Terminology	7
1.4. About DX Storage Object Types	8
1.5. Bucket and Object Naming Rules	8
1.6. Simple Examples of Creating Buckets and Named Objects	8
1.7. Universal Resource Identifiers (URIs)	9
1.8. About Objects and Security	10
1.8.1. The Basics of DX Storage Security	10
1.8.2. Commonly Used Security Terminology	11
1.8.3. Basic Security Guidelines	11
1.9. Concepts for Unnamed Objects	11
1.9.1. Universally Unique Identifiers (UUIDs)	11
1.9.2. About Immutable Objects	12
1.9.3. About Anchor Streams	12
1.10. Document Typographical Conventions	13
Chapter 2. Connecting to a DX Storage Cluster	14
2.1. About the Primary Access Node (PAN)	14
2.2. Requirements for Node Accessibility	14
2.2.1. Using the DX Storage Software Development Kit (SDK)	14
2.2.2. Using Multicast-DNS (mDNS)	15
2.2.3. Using DNS Round Robin	15
2.2.4. Using a Pool of Static IP Addresses	16
2.2.5. Using a Single Static IP Address	16
Chapter 3. Application Best Practices	17
3.1. Using the Software Development Kit (SDK)	17
3.2. Dynamically Locating DX Storage Nodes	17
3.3. Optimizing Bucket and Domain Operations	17
3.4. Using HTTP Client Libraries	17
3.5. Handling Redirects	18
3.6. Using Range Headers	18
3.7. Multi-Threading	19
3.8. Using Persistent Connections	19
Chapter 4. Introduction to the Simple Content Storage Protocol (SCSP)	20
4.1. Mapping SCSP Operations to HTTP Methods	20
4.2. HTTP Overview	21
4.3. Requests and Responses	21
4.3.1. HTTP Response Codes	21
4.3.2. Redirect Responses	22
4.4. Formatting SCSP Commands for Named and Unnamed Objects	22
4.5. Undefined Responses from DX Storage	23
4.6. Normal Response Headers	24
Chapter 5. SCSP READ	27
5.1. Introduction to READ	27
5.1.1. Reading With Content Validation	27
5.1.2. Requestion Node Status and Cluster Capacity	27
5.2. Unnamed Object READ Details	28
5.3. Normal Responses to READ	28
5.3.1. Normal READ Responses for Named Objects	28
5.3.1.1. Normal READ Response for a Domain	28
5.3.1.2. Normal READ Response for a Bucket	29
5.3.1.3. Normal READ Response for a Named Object	29
5.3.2. Normal READ Response for Unnamed Objects	29
5.3.3. Other Normal READ Responses	30
5.4. Error Responses to READ	30
Chapter 6. SCSP WRITE	32
6.1. Introduction to WRITE	32
6.1.1. About the Expect: 100-continue Header and WRITE	33
6.1.2. About Replicate On Write	33
6.2. Named Object WRITE Details	33
6.3. Unnamed Object WRITE Details	33
6.4. Normal Responses to WRITE	33
6.5. Error Responses to WRITE	34
Chapter 7. SCSP DELETE	36
7.1. Introduction to DELETE	36
7.2. Unnamed Object DELETE Details	37
7.3. Named Object DELETE Details	37
7.4. Normal Responses to DELETE	37
7.5. Error Responses to DELETE	38
Chapter 8. SCSP UPDATE	39
8.1. Introduction to UPDATE	39
8.2. Unnamed Object UPDATE Details	39
8.3. Normal Responses to UPDATE	40
Chapter 9. SCSP COPY	41
9.1. Introduction to COPY	41
9.2. Unnamed Object COPY Details	41
9.3. Normal Responses to COPY	41
Chapter 10. SCSP APPEND	42
10.1. Introduction to APPEND	42
10.2. Unnamed Object APPEND Details	43
10.3. Normal Responses to APPEND	43
Chapter 11. SCSP INFO	44
11.1. Introduction to INFO	44
11.1.1. Getting Replica Counts	44
11.1.2. Getting Node Status and Cluster Capacity	44
11.2. Unnamed Object INFO Details	45
11.3. Normal Responses to INFO	45
11.3.1. Normal INFO Responses for Named and Unnamed Objects	45
11.3.2. Normal INFO Responses for Named Objects	46
11.3.3. Normal INFO Responses for Unnamed Objects	47
11.4. Error Responses to INFO	47
Chapter 12. Introduction to Object Security	48
12.1. About Security Roles	48
12.2. Security Realm Overview	49
12.2.1. Common Security Terminology	49
12.2.2. About Security Realms	49
12.2.3. About Realm Caching and Security	49
12.3. About Authorization Header Syntax	50
12.3.1. About Realm Names	51
12.3.1.1. About Realms and Buckets	51
12.3.1.2. About owner@ and @owner Syntax	51
12.3.1.3. About user@realm Syntax	51
12.4. Authorization Specification Examples	51
12.5. About Authorization Header Evaluation	52
12.6. Creating Realms	53
12.7. Updating the Realm on a Bucket	54
12.8. Administrative Override and Security	54
Chapter 13. Managing Security for Application Developers	55
13.1. What Application Developers Need to Know	55
13.2. About Bucket Authorization	55
13.3. Example: Creating Bucket Owners	56
13.4. Examples of Creating Buckets and Named Objects	56
Chapter 14. Managing Security for Domain Managers	59
14.1. What Domain Managers Need to Know	59
14.2. About Domain Manager Tasks and Responsibilities	59
14.3. Examples of Updating Domain and Administrator User Lists	59
14.3.1. Updating the Domain Realm	60
14.3.2. Updating the Domain Manager Realm	61
14.3.3. Updating a Realm Using PUT	62
Chapter 15. Using the Content-MD5 Metadata Header	64
Chapter 16. Using Lifepoint Metadata Headers	65
16.1. About Storage Policies	65
16.2. A Simple Lifecycle Example	65
16.3. Lifepoint/Lifecycle Specification	66
16.4. Constraint Types	66
16.4.1. Replication	67
16.4.2. Deletion	67
Chapter 17. Using the Allow Metadata Header	69
17.1. Overview of the Allow Header	69
17.2. Administrative Override	69
Chapter 18. Using Caching Metadata Headers	71
18.1. About Caching Headers	71
18.2. Using HTTP/1.0 Caching Headers	71
18.2.1. Last-Modified	71
18.2.2. If-Modified-Since	71
18.2.3. If-Unmodified-Since	71
18.2.4. Expires	72
18.3. Using HTTP/1.1 Caching Headers	72
18.3.1. ETag	72
18.3.2. If-Match	72
18.3.3. If-None-Match	73
18.3.4. If-Range	73
Chapter 19. Using Custom Metadata Headers	75
Chapter 20. Basic Content Integrity Assurance	76
20.1. Integrity Seals	76
20.2. Validating Reads	76
20.3. Application Initiated Hash Upgrading	77
Appendix A. Content Header Metadata	78
Appendix B. Sample Code and Client Library Behaviors with 100-Continue	80

Match case Limit results 1 per page

Version 5.0

December 2010

DX Storage makes no assumptions about User-Agent (except that it is an HTTP/1.1 client). The

Host header is mandatory and must conform to the requirements of

Section 14.23

of the HTTP/1.1

spec.

6.1.1. About the Expect: 100-continue Header and WRITE

The

Expect: 100-continue header

tells the server that the client will wait after sending just the

header lines and before sending the content stream in the body of the message. The DX Storage

server can respond with a redirect, an error response, or if it is capable and ready to store the

contents, it returns a 100 Continue response, telling the client to proceed with its transmission of the

entity body. The client should wait for a 100 Continue response from the server before proceeding

to send data. Otherwise, the server might send a 413 (

Request entity too large

error

response) and close the connection.

DX Storage allows the client to omit the Expect: 100-continue header, sending all the content data

at once, in which case the server reads and discards all data if it must respond with a redirect

or error. For WRITEs of more than 65536 bytes, DX Storage logs the following warning if the

Expect header is not utilized:

Please use Expect: 100-continue for large amounts

of data

. Additionally, if no node in the cluster has enough space to write the stream, a

507 -

Insufficient Storage

error response is returned.

6.1.2. About Replicate On Write

To force a first replication by DX Storage on receipt of the file, set the query argument:

replicate=immediate

. The value is case-sensitive, and all other values for replicate other

than

immediate

are ignored. If either the replication or the initial write fail, both will fail, and the

application returns a 412 error. This feature guarantees that two copies of the stream will be saved

on different nodes before returning a 201 Created.

6.2. Named Object WRITE Details

In contrast to an unnamed object, if you WRITE a named object that already exists, the existing

object is overwritten with a new version.

6.3. Unnamed Object WRITE Details

If you WRITE an unversioned stream, a new stream is created and a new UUID is returned. If you

WRITE an anchor stream, a new stream is created and a new alias UUID is returned.

To create unnamed anchor stream objects,

alias=yes

is required, as shown in the following

example.

POST /?alias=yes HTTP/1.1

Host: cluster.example.com

User-Agent: DX Storage Client/0.1

6.4. Normal Responses to WRITE

For a list of response headers, see

Section 4.6, “Normal Response Headers”

The following responses can be returned by the DX Storage cluster in the case where the new

content stream can be created as requested. The content might be created and written to the cluster

by the node to which the request was sent, or it might be redirected to another node in the cluster.

HTTP/1.1 201

Created Date: Wed, 1 Sept 2010 15:59:02 GMT