Custom Metadata - Dell DX6000 Deployment Manual

Dell DX Object Storage – File Gateway Deployment Guide
replicas and leave all other departments utilizing a mount point with a lifepoint policy for fewer
replicas.
As a baseline for file metadata, CFS will automatically add the following system attributes on all
streams stored in the Dell DX Object Storage:

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

Dell DX Object Storage-CFS-CFSID: the name of the mount point id through which the file was
originally stored

Castor-CFS-FileId: the file system id for the file in the CFS name space

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. Extended
attributes like ACLs are stored in CNS. They are not stored as a CAStor header with the data
object. These CAStor headers are not used by the CNS, but are a last line of defense in the very
unlikely event of loss of the entire metadata tree.
The mechanisms to add both custom metadata and life cycle retention policies to files stored in the
Dell DX Object Storage via CFS are outlined in the sections below.

Custom Metadata

The CFS-admin metadata utility allows a root user to administer the custom metadata that is attached
to newly created files when they are ready to be stored in the Dell DX Object Storage (last file close
plus 5 seconds).

Custom metadata applies to all files stored in a particular mount point and, like all Dell DX
Object Storage metadata, is immutable after the file is stored in the DX Object Storage. Thus,
changing the custom metadata for a CFS file system will affect only new or modified files; it
will not change metadata for files that were previously written.
To add metadata to a mount point, execute the following command as the root user:
# cfs-admin metadata --set [--name=NAME] [--value=VALUE] CFS-root
where CFS-root is the full path for the CFS mount point to which the metadata should be attached. For
example, to add an attribute of 'Department' with a value of 'Legal' to all files in the CFS-legal mount
point, execute the following command:
# cfs-admin metadata --set --name=Department --value=Legal /mnt/CFS-legal
Metadata names must be unique within a mount point and may contain up to 242 characters. A --set
command that uses a pre-existing metadata name with new or different values will overwrite the
Page 64