Remote Replication; Local Replication - Sun Microsystems Virtual Tape Library User Manual

Key VTL features and options
Auto Replication
The Auto Replication option copies virtual tapes from a virtual library to
another VTL server whenever a backup application or utility moves a virtual tape to
an import/export slot.
You enable Auto Replication at the library level when you create a virtual tape
library (see "Setting up the Auto Replication option" on page 50). You can then
selectively enable the feature on a tape‐by‐tape basis as tapes are created. You cannot
alter the Auto Replication status of an existing virtual tape.
Replication
The VTL Replication feature maintains synchronized replica resource copies of
virtual tapes on a designated VTL server. At the end of a policy‐defined replication
interval, VTL software copies data that has changed and is not currently in use from
the primary virtual tapes to the replica resources.
During normal operation, backup clients have no access to replica resources—the
latter are purely internal protections within the VTL system. If the primary virtual
tape is corrupt or otherwise unusable, however, administrators can promote replica
resources as part of their disaster recovery process. Once promoted, the replica
resource becomes the primary virtual tape, with the same barcode and attributes.
Backup clients can thus use it for recovery as if it were, in fact, the original copy.
You can configure the VTL Replication feature for either:
Remote Replication or
Local Replication.
Remote Replication
Remote Replication maintains synchronized copies of virtual tape volumes on the
storage arrays of a pair of VTL appliances that are connected across Ethernet local
area networks (LANs) or Wide Area Networks (WANs). Data is thus transferred at
LAN/WAN speed, but is not subject to the distance limitation imposed by Fibre
Channel storage area network (SAN) technology.
Local Replication
Local Replication maintains local, synchronized copies of virtual tape volumes on
the storage arrays of a single VTL appliance. Data is transferred at SAN speed over
distances limited to the maximum possible with a Fibre Channel SAN.
96267 • G Chapter 1 Introduction: VTL appliances and enterprise data-protection 13