HP B6960-96035 - Manual (Page 271)

Figure 80 Split mirror - remote mirror (LAN-free remote backup - data
HA)
The remote mirror transfers data to a physically separate site where it can be backed
up to locally available tapes. This allows the separation of production data from
backup data, eliminating the risk of a fire or other disaster damaging both the
production and the backup environment at the same time.
No network resources are required to sync the mirrors during a backup. Although
data is not transferred through the network, Data Protector still needs the
communication between the Cell Manager and its clients.
This solution allows you to centralize a backup service by mirroring the application
data from several production sites (A and C in this case) to a central location or
central disk array. In this way, your investment in a backup service (server and tape
library) can be consolidated and combined with the high availability of a remote
mirror configuration.
The remote site cannot be used as an automatic disaster recovery site during the time
of the backup, as the link between the two sites is split for the duration of the backup
(and both disks are out of sync). This means that in case of a site A failure, site B
cannot take over automatically (as it normally would) for x hours (x being the time
the data takes to stream to the tape). This problem applies to local mirroring as well.
However, it is particularly important for the remote solution, as the concept of a
Concepts guide 271