Snapshot ProcessThe protection process commences with a base image followed by incremental snapshots forever. The agent usesMicrosoft Volume Shadow Copy Service (VSS) to freeze and quiesce application data to disk to capture a file-system-consistent and an application-consistent backup. When a snapshot is created, the VSS writer on the target serverprevents content from being written to the disk. During the process of halting disk writes, all disk I/O operations arequeued and resume only after the snapshot is complete, while the operations already in flight are completed and allopen files are closed. The process of creating a shadow copy does not significantly impact the performance of theproduction system. AppAssure uses Microsoft VSS because it has built-in support for all Windows internal technologiessuch as NTFS, Registry, Active Directory, and so on, to flush data to disk before the snapshot. Additionally, otherenterprise applications, such as Microsoft Exchange and SQL, use VSS Writer plug-ins to get notified when a snapshotis being prepared and when they have to flush their dirty database pages to disk to bring the database in a consistenttransactional state.NOTE: It is important to note that VSS is used to quiesce system and application data to disk; it is not used to createthe snapshot.The captured data is rapidly transferred to and stored on the AppAssure 5 Core. Using VSS for backup does not renderthe application server in backup mode for an extended period of time because the length of time to perform the snapshotis seconds and not hours. Another benefit of using VSS for backups is that it allows the agent take a snapshot of largequantities of data at one time since the snapshot works at the volume level.Replication Disaster Recovery Site Or Service ProviderThe replication process in AppAssure requires a paired source-target relationship between two cores. The source corecopies the recovery points of the protected agents and then asynchronously and continuously transmits them to a targetcore at a remote disaster recovery site. The off-site location can be a company-owned data center (self-managed core)or a third-party managed service provider’s (MSP’s) location or cloud environment. When replicating to a MSP, you canuse built-in workflows that let you request connections and receive automatic feedback notifications. For the initialtransfer of data, you can perform data seeding using external media, which is useful for large sets of data or sites withslow links.In the case of a severe outage, AppAssure 5 supports failover and failback in replicated environments. In case of acomprehensive outage, the target core in the secondary site can recover instances from replicated agents andimmediately commence protection on the failed-over machines. After the primary site is restored, the replicated corecan fail-back data from the recovered instances back to agents at the primary site.RecoveryRecovery can be performed in the local site or the replicated remote site. After the deployment is in steady state withlocal protection and optional replication, the AppAssure 5 Core allows you perform recovery using Recovery Assure,Universal Recovery, or Live Recovery.Product Features Of AppAssure 5Using AppAssure 5, you can manage all aspects of protection and recovery of critical data using the following:• Repository• True Global Deduplication• Encryption15
