Repository; True Global Deduplication - Dell DL4000 User Manual

Repository

The repository uses Deduplication Volume Manager (DVM) to implement a volume manager that provides
support for multiple volumes, each of which could reside on different storage technologies such as
Storage Area Network (SAN), Direct Attached Storage (DAS), Network Attached Storage (NAS), or cloud
storage. Each volume consists of a scalable object store with deduplication. The scalable object store
behaves as a records-based file system, where the unit of storage allocation is a fixed-sized data block
called a record. This architecture allows you to configure block-sized support for compression and
deduplication. Rollup operations are reduced to metadata operations from disk intensive operations
because the rollup no longer moves data but only moves the records.
The DVM can combine a set of object stores into a volume and they can be expanded by creating
additional file systems. The object store files are pre-allocated and can be added on demand as storage
requirements change. It is possible to create up to 255 independent repositories on a single Core and to
further increase the size of a repository by adding new file extents. An extended repository may contain
up to 4,096 extents that span across different storage technologies. The maximum size of a repository is
32 exabytes. Multiple repositories can exist on a single core.

True Global Deduplication

True global deduplication is an effective method of reducing backup storage needs by eliminating
redundant or duplicate data. Deduplication is effective because only one unique instance of the data
across multiple backups is stored in the repository. The redundant data is stored, but not physically; it is
simply replaced with a pointer to the one unique data instance in the repository.
Conventional backup applications have been performing repetitive full backups every week, but your
appliance performs incremental block-level backups of the machine. The incremental-forever approach
in tandem with data deduplication helps to drastically reduce the total quantity of data committed to the
disk.
The typical disk layout of a server consists of the operating system, application, and data. In most
environments, the administrators often use a common flavor of the server and desktop operating system
across multiple systems for effective deployment and management. When backup is performed at the
block level across multiple machines at the same time, it provides a more granular view of what is in the
backup and what is not, irrespective of the source. This data includes the operating system, the
applications, and the application data across the environment.
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