User guide

246 | Glossary
Replication
Replication is self-optimizing with a unique read-match-write (RMW) algorithm that is
tightly coupled with deduplication. It represents the relationship between the target and
source cores in the same site or across two sites with slow link in which the source core
asynchronously transmits the data to the target or source core on a per agent basis.
Repository
A repository, which is managed by the AppAssure 5 Core, is a folder used to store snapshots
that are captured from the protected servers and machines. The repository can reside on
different storage technologies such as Storage Area Network (SAN), Direct Attached Storage
(DAS), or Network Attached Storage (NAS).
Retention
Retention defines the length of time the backup snapshots of protected machines are stored
on the AppAssure 5 Core. Retention policy is enforced on the recovery points through the
rollup process.
Rollback
Rollback is the process of restoring volumes on a machine from recovery points.
Rollup
The rollup process is an internal nightly maintenance procedure that enforces the retention
policy by collapsing and eliminating dated recovery points. AppAssure 5 reduces rollup to
metadata operations only.
Seeding
In replication, the initial transfer of deduplicated base images and incremental snapshots of
protected agents, which can add up to hundreds or thousands of gigabytes of data. Initial
replication can be seeded to the target core using external media, which is useful for large
sets of data or sites with slow links.
Server Cluster
See “Windows Failover Cluster” on page 247.
Single Copy Cluster
A shared storage failover cluster solution, that uses a single copy of a storage group on
storage that is shared between the nodes in the cluster. It is one of two types of clustered
mailbox server deployments available in Exchange 2007.
Smart Agent
The AppAssure 5 Smart Agent is installed on the machines protected by the AppAssure 5
Core. The smart agent tracks the changed blocks on the disk volume and snapshots the
changed blocks at a predefined interval of protection
Snapshot
A snapshot is a common industry term that defines the ability to capture and store the state
of a disk volume at a given point, while applications are running. The snapshot is critical if
system recovery is needed due to an outage or system failure. AppAssure snapshots are
application aware, which means that all open transactions and rolling transaction logs are
completed and caches are flushed prior to creating the snapshot. AppAssure uses Microsoft
Volume Shadow Services (VSS) to facilitate application crash consistent snapshots.
SQL Attachability
SQL attachability is a test run within the AppAssure 5 Core to ensure that all SQL recovery
points are without error and are available for backup in the event of a failure.