User guide

20 | Introduction to AppAssure 5
Repository
The AppAssure 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 lets you 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 AppAssure 5 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 AppAssure performs incremental block-level backups of the
machines forever. This incremental-forever approach in tandem with data
deduplication helps to drastically reduce the total quantity of data committed to the
disk.