Replication; Replication Overview - HP D2D Manual

5 Replication

NOTE: When considering replication you are likely to be synchronizing data between different
models of HP StoreOnce Backup Systems. The examples in this section are not specific to a particular
model of HP StoreOnce Backup System.
In this chapter:

Replication overview

HP StorageWorks Replication Manager
Replication concepts and terminology
Replication deployment strategies
Replication licensing
Seeding the Target Appliance
Recovering a source appliance
Replication overview
Replication is a standard term used to describe a way of synchronizing data between hardware
in two physical locations. It is the process of creating an exact match on the target appliance of
the specified data from the source appliance. It is important to understand that no history is held;
the target appliance always mirrors as soon as possible the current state of the data on the source
appliance, which means that it is ready for use if the source share, library or appliance is
unavailable. But it does not hold archive versions and is not an alternative to conventional backup
with multiple restore points.
A Configuration Wizard is provided to take you through HP D2D Replication configuration steps.
Replication and NAS Shares
HP D2D Replication allows NAS shares that have been configured on one HP StoreOnce Backup
System (the Source Appliance) to be replicated to corresponding NAS shares on another HP
StoreOnce Backup System (the Target Appliance) at another location. Replication is always mapped
at share—share level (not at sub-directory or file level). Target shares are always visible but are
read only.
Once you have set up a replication configuration between Source and Target HP StoreOnce Backup
Systems, it is initiated automatically whenever a backup takes place.
NOTE: If the replication Source Appliance fails and goes offline whilst it was performing a NAS
replication job, the replication target share appliance may be left in an inconsistent state. This state
may result in failure to recover from some files in the share or perform a list of files in the share
because relationships between files and folders have been lost. This will automatically be repaired
by the target appliance as soon as it detects the loss of the source appliance, however it may take
up to 10 minutes to complete this repair during which time the share will not be available for
access.
Replication and Virtual Tape Devices
HP D2D Replication allows cartridges in slots on a library device that has been configured on one
HP StoreOnce Backup System (the Source Appliance) to be replicated to corresponding mapped
slots on a library device on another HP StoreOnce Backup System (the Target Appliance) at another
location. Data is always mapped at slot level.
18 Replication