HP D2D Manual page 38

transfer backup data from the host to the HP StoreOnce Backup System. Access to the HP
StoreOnce Web Management Interface is always across an Ethernet connection.
Flexible emulation Flexible emulation does not set hard limits on the number of VTL devices (loader and drives) and
NAS shares that may be configured for a particular data store, although there are restrictions on
the maximum numbers that may be configured for an appliance. This allows the user to balance
performance against deduplication ratio when deciding how backup streams from the host will
be configured. See also
H
Hosts A server that is being used to back up to the StoreOnce system via iSCSI or Fibre Channel, this
may also be a backup application media server which can back up other servers on the network
that do not have a direct iSCSI or Fibre Channel connection to the StoreOnce Backup System.
Housekeeping If data is deleted from the StoreOnce Backup System (e.g a virtual cartridge is overwritten or
erased), any unique chunks will be marked for removal, any non-unique chunks are de-referenced
and their reference count decremented. The process of removing chunks of data is not an inline
operation because this would significantly impact performance. This process, termed
"housekeeping", runs on the appliance as a background operation, it runs on a per cartridge
and NAS file basis and will run as soon as the cartridge is unloaded and returned to its storage
slot or a NAS file has completed writing and has been closed by the appliance.
I
iSCSI On an Ethernet network the HP StoreOnce Backup System is configured as an iSCSI device. This
means that the HP StoreOnce Backup System plugs directly into the network, but it presents devices
as directly-attached SCSI autoloaders to host machines. In order to function, it requires an iSCSI
initiator. For more information about iSCSI, see the HP StoreOnce Backup System Installation
and Configuration Guide. Linux and UNIX users should also refer to the Linux and UNIX
Configuration Guide on the HP StoreOnce Backup System CD-ROM for more information.
L
Library library is a Virtual Tape Device that appears to the backup application on the host as a physical
tape library. A tape library is a backup device that has multiple drives and multiple storage slots.
Each storage slot contains a cartridge. This provides considerable storage capacity and full
support for tape rotation strategies. The difference between an autoloader and a library is that
a library can support multiple tape drives whereas an autoloader only has one tape drive. (It
may be necessary to upgrade your backup application to support libraries.)
M
Mail slots A mail slot is a term borrowed from tape terminology to identify a dedicated slot that is used
(import/export specifically to import and export cartridges. They are sometimes called import/export elements
elements) by backup applications. Backup applications that support this feature move cartridges from the
mail slot when the user runs an Export job, and look for cartridges in the mail slot when the user
runs an Import job.
Mail slots have no practical usage with G2 HP StoreOnce Backup Systems because direct export
to tape is not supported.
N
NAS Shares Devices on HP StoreOnce Backup Systems may be configured as Virtual Tape devices or as NAS
(Network Attached Storage) targets for backup applications. NAS target devices on an HP
StoreOnce Backup System provide network file share access that is optimized for backup to disk
and are referred to as NAS Shares in the Web Management Interface.
All HP StoreOnce devices that are configured for NAS automatically make use of HP deduplication,
ensuring efficient and cost-effective use of disk space.
38 Glossary
Flexible emulation.