User's Manual

HP StorageWorks File System Extender Software user guide 107
Reorganizing media
In FSE, data stored on an HSM file system is automatically and periodically migrated to FSE media. This
applies not only to every new file created on the HSM file system, but also to every existing file whose
attributes or contents is modified. Each modification of the file subsequently causes it to be migrated to
media as a new file generation.
Over time, the situation can arise where a large proportion of space on FSE media is occupied by old,
obsolete generations of files. FSE enables you to reclaim media space by reorganizing the data on the
media. The media reorganization process frees space on media by preserving only selected file
generations and removing the others. FSE media space can then be reused for newly migrated data.
NOTE: LTO Ultrium 3 WORM media cannot be rewritten or reformatted, but they can be reorganized.
However, the media space reclaimed cannot be reused.
Although you cannot reuse WORM media space, the reorganization of WORM media is necessary when
you need to destroy sensitive data that was migrated to these media, while preserving the rest of the data.
In these circumstances, the last step of the data erasure process is the physical destruction of the WORM
media that hold the sensitive data.
Media reorganization is a medium-volume-based process. This means that the smallest unit of the
secondary storage space that can be reorganized is a single FSE medium volume. Similarly, the smallest
unit that can be reused is an FSE medium volume. As system volumes do not contain file data, only data
volumes can be reorganized.
Prerequisites
• Before scanning media as part of the media reorganization process run the FSC vs. media check with
the --autocorrect and --match-media options. For more information, see ”Consistency check of
FSC vs. FSE media” on page 182.
Limitation
• After the reorganization of one or more FSE medium volumes on an FSE medium, any duplicates of the
medium created before the reorganization are rendered useless, as (part of) the source medium has
been reinitialized at the end of the reorganization job.
To restore data safety level, you need to duplicate each medium that contains reorganized medium
volumes and whose sources for the reorganization process were duplicated before the reorganization.
The media reorganization process
The media reorganization process consists of two steps: scanning and copying. Each step is controlled and
performed by its own FSE job.
[11:42:09] Requesting resources...
[11:42:09] Resources allocated.
[11:48:42] Loading medium 456456 to drive drv1.
[11:43:58] Checking medium format.
[11:43:58] Blank medium detected.
[11:43:48] Medium 456456: Blank volume detected.
[11:43:58] Medium 456456, volume 1: Writing data...
[11:43:58] Medium 456456, volume 1: Volume written.
[11:43:58] Medium 456456, volume 2: Writing data...
[11:43:58] Medium 456456, volume 2: Volume written.
[11:43:58] Writing finished, releasing resources.
[11:43:58] Finished.