User's Manual

hp StorageWorks File System Extender User Guide 89
Disk media specifics
The main difference between tape and disk media is in preparing media for use by FSE. A disk medium
must be mounted to a dmNumber mount point in the disk media location before it can be used. The
location is platform-dependent.
Linux specific
On Linux platform, disk media are located in the directory /var/opt/fse/dm.
Windows specific
On Windows platform, disk media are located in the directory %InstallPath%\var\dm.
The value of %InstallPath% depends on the choice made in the FSE installation process. It defaults to
C:\Program Files\Hewlett-Packard\FSE.
Afterwards disk media also needs to be formatted and initialized, but you must be aware of the distinctions
between the different media types:
• Disk media can only be added to an FSE disk media pool.
• Maximum number of medium volumes on an FSE disk medium is 255. You define the size of medium
volumes in the media pool configuration file.
NOTE: When configuring an FSE disk media pool, you need to specify a VolumeSize parameter
large enough that 255 * VolumeSize is larger than the total disk medium size. Otherwise, a
warning is issued and the number of volumes is set to 255, leaving some unused space.
• Disk media are formatted and initialized in the same way as tape media. Formatting of disk media
creates subdirectories for medium volumes. At initialization, the size of medium volumes is written to the
Resource Management Database and to each initialized volume.
• A particular disk medium volume is closed when the total size of all files on the volume reaches the
volume size defined in the disk media pool configuration.
• Once a disk medium is formatted, it is not possible to add additional medium volumes to the medium.
When running out of space, another disk medium must be added to the disk media pool.
• The barcode of a disk medium is the relative part of the mount point, for example dm000001,
dm000002. Its length is limited to 64 characters.
Example layout of disk media
Each medium volume has its own directory named after the corresponding volume number, for
example: /var/opt/fse/dm/dm000001/00000001. The volume directory includes the following
files:
• medium volume header (00000000.hdr)
• medium volume data (00000003.vdf)
• medium volume FRI data (FileBlockOffset.fri)
|-- dm
| `-- dm000001 medium barcode
| |-- 00000001 volume number
| | |-- 00000001.hdr volume header
| | `-- 00000003.vdf volume data file
| |-- 00000002
| | |-- 00000001.hdr
| | |-- 00000003.vdf
| | `-- 00028545.fri fast recovery information file
| `-- 00000003
| `-- 00000001.hdr volume contains no data