About Failover And Failback In Appassure 5; About Replication And Encrypted Recovery Points; About Retention Policies For Replication; Performance Considerations For Replicated Data Transfer - Dell PowerVault DL4000 User Manual

Because large amounts of data need to be copied to the portable storage device, an eSATA, USB 3.0, or other high-
speed connection to the portable storage device is recommended.

About Failover And Failback In AppAssure 5

In the case of a severe outage in which your source core and agents fail, AppAssure 5 supports failover and failback in
replicated environments. Failover refers to switching to a redundant or standby target AppAssure Core upon system
failure or abnormal termination of a source core and associated agents. The main goal of failover is to launch a new
agent identical to the failed agent that was protected by the failed source core. The secondary goal is to switch the
target core into a new mode so that the target core protects the failover agent in the same way as the source core
protected the initial agent before the failure. The target core can recover instances from replicated agents and
immediately commence protection on the failed-over machines.
Failback is the process of restoring an agent and core back to their original states (before failure). The primary goal of
failback is to restore the agent (in most cases, this is a new machine replacing a failed agent) to a state identical to the
latest state of the new, temporary agent. When restored, it is protected by a restored source core. Replication is also
restored, and the target core acts as a replication target again.

About Replication And Encrypted Recovery Points

While the seed drive does not contain backups of the source core registry and certificates, the seed drive does contain
encryption keys from the source core if the recovery points being replicated from source to target are encrypted. The
replicated recovery points remain encrypted after they are transmitted to the target core. The owners or administrators
of the target core need the passphrase to recover the encrypted data.

About Retention Policies For Replication

The retention policy on the source core determines the retention policy for the data replicated to the target core,
because the replication task transmits the merged recovery points that result from a rollup or ad-hoc deletion.
NOTE: The target core is not capable of rollup or of ad-hoc deletion of recovery points. These actions can only be
performed by the source core.

Performance Considerations For Replicated Data Transfer

If the bandwidth between the source core and the target core cannot accommodate the transfer of stored recovery
points, replication begins with seeding the target core with base images and recovery points from the selected servers
protected on the source core. The seeding process only has to be performed once, as it serves as the foundation that is
required for regularly scheduled replication.
When preparing for replication, you must consider the following factors:
Change Rate The change rate is the rate at which the amount of protected data is accumulated. The rate
depends on the amount of data that changes on protected volumes and the protection interval
of the volumes. If a set of blocks change on the volume, reducing the protection interval
reduces the change rate.
Bandwidth The bandwidth is the available transfer speed between the source core and the target core. It
is crucial that the bandwidth be greater than the change rate for replication to keep up with the
recovery points created by the snapshots. Due to the amount of data transmitted from core to
core, multiple parallel streams may be required to perform at wire speeds up to the speed of a
1 GB Ethernet connection.
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