Appendix A. Content Metadata
In planning for replication of data from one location to another and/or disaster recovery scenarios
within DX Storage, it is advisable to ensure that you are both fully utilizing the system metadata
automatically stored with every stream as well as adding custom metadata that will allow you to
create dynamic rules for distributing your content. Metadata can be stored with a stream from one of
several sources outlined below.
A.1. System Metadata
As of the DX Storage 2.1 release, a 'Castor-System-Cluster' metadata attribute is automatically
stored with each stream in DX Storage based on the cluster name specified in your cluster
or node configuration files. This attribute ensures that a stream that is replicated to a disaster
recovery cluster can always be traced back to its cluster of origin in the event of a disaster.
This is particularly important in scenarios where multiple satellite clusters are replicated into a
centralized disaster recovery cluster. A naming scheme similar to the following is recommended:
uniquename_yourcompanydomainname (ex: cluster1_acme_com) for each cluster to ensure global
uniqueness. In addition to the cluster name, the date the stream was stored in DX Storage (Castor-
system-created) is also written with each stream and can be used for date-based rules.
A.2. Content File Server Metadata
If you are using a Content File Server (CFS) client, the following metadata is stored with CFS
streams automatically and can be used in content distribution or replication rules. For instance, an
admin may wish to replicate only those files written to a configured 'Legal' share and a rule based on
the CAStor-CFS-CFSID header could be used to isolate those files:
• Castor-CFS-Filepath: the full path to the file when it was originally stored
• Content-Disposition: the filename
• Castor-CFS-Server: the name of the server from which the file was originally stored
• Castor-CFS-Version: the version of the CFS software that originally stored the file
• Content-Type: the file's mimetype
• CAStor-CFS-CFSID: the name of the mountpoint id through which the file was originally stored
• Castor-CFS-FileId: the filesystem id for the file in the CFS namespace
• Castor-CFS-Uid: the file's user id at the time it was stored
• Castor-CFS-Gid: the file's group id at the time it was stored
• Castor-CFS-Mode: the file's permission mode in decimal at the time it was stored
A.2.1. Custom Metadata
If you are using a custom developed client to write to DX Storage, additional HTTP headers (ex:
Content-Language, Content-Type, etc) and optional custom metadata can also be stored with a
stream to aid in content distribution and processing with the new DX Content Router. CFS also
allows definition of custom metadata at the mountpoint level. See the Content Metadata section of
the DX Storage Application Guide or the Running and Managing CFS section of the CFS Setup and
Configuration Guide respectively for a complete overview of how to implement custom metadata.
Copyright © 2010 Caringo, Inc.
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Version 2.2
December 2010
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