User's Manual

14 Introducing HP StorageWorks File System Extender
For further information on release process and its configuration, see ”Migration, release, recall, and
deletion” on page 109.
Recall
Recall is a process of copying file data from FSE media back to an HSM file system. It is the reverse process
to migration.
Recall is done in two steps:
1. Data is copied from the FSE media to a temporary location (disk buffer).
2. Data from this temporary location is copied back to the HSM file system, thus recreating file contents.
Once the recall job is completed, the temporary location is cleared, and the offline file is online again. Its
file entry in the Hierarchical Storage Manager is added to the current release candidate list.
FSE stores older versions of files on its media, referred to as older generations, which can be recalled
manually. For details, see ”Recalling older generations of a file” on page 146.
For further information on recall process and its configuration, see chapter ”Migration, release, recall, and
deletion” on page 109.
Deletion
Deletion is a process of obsoleting and removing obsolete files from HSM file systems. You can use this
process for various purposes, including Information Lifecycle Management (ILM) and freeing disk space of
redundant files.
The criteria that induce file obsolescence on HSM file systems are defined in the deletion policy. Each HSM
file system has its own deletion policy. Deletion is enabled on regular and WORM HSM file systems.
For further information on deletion process and its configuration, see chapter ”Migration, release, recall,
and deletion” on page 109.
FSE components
HSM file system
An HSM file system (HSM FS) is a hard disk area reserved for storage of user files and directories (user
data), and managed by the FSE implementation. The HSM file system is used to store the metadata
(names, attributes, and permissions of user data) and user data that is currently online.
Linux specific
On Linux platform, HSM file system is based on the Ext3 file system; the HSM attributes are stored in Ext3
extended attributes.
Windows specific
On Windows platform, HSM file system is based on the NTFS.
In an FSE installation, an HSM file system represents the primary storage space, and the FSE media
represent the secondary storage space.
An HSM file system can be configured either as a regular file system or as a WORM file system:
• Regular file system
All files and directory operations are supported as known for the native file system of the respective
platform.
• WORM (Write-Once Read-Many) file system
File and directory operations are restricted to read-only after a configured period of time. The limitation
does not include adding files to directories, which can be done as on a regular file system.
For details on configuring a WORM HSM file system, see ”Step 4: configuring FSE partitions” on
page 69.
Hierarchical Storage Manager (HSM) is a component of the HSM file system. As a part of an FSE client, it
handles HSM file system events and manages the migration and release candidate lists. Each mounted
HSM file system has one FSE HSM.