Sun Microsystems Virtual Tape Library - Manual (Page 25)

Key VTL features and options
96267 • G Chapter 1 Introduction: VTL appliances and enterprise data-protection 11
Storage path failover
In a standard‐availability VTL system, there is one logical path from a VTL client to
VTL storage, and every Fibre Channel port is either a target port for a VTL client or
a storage‐facing initiator. But in a high‐availability system, there are two paths, a
primary and a secondary or standby path, as shown below.
Fibre Channel path failover in high-availability VTL systems
Failover during replication
If a replication operation is in progress when failover or failback occurs, replication
stops. Once failover/failback has completed, replication resumes with the next
normally scheduled operation.
Mirroring and failover
If mirroring is in progress during failover/recovery, after the failover/recovery the
mirroring will restart from where it left off.
If the mirror is synchronized but Fibre Channel connectivity is lost between the
server and storage, the mirror may become unsynchronized. It will resynchronize
automatically after failover/recovery.
A synchronized mirror will always remain synchronized during a recovery process.
Primary path from A
VTL client A
WWPN x1 Primary server for A
VTL client B
Primary path from B WWPN y2
Primary server for B
Secondary server for B
Secondary server for A
Secondary path from A
Secondary path from B
WWPN x2
WWPN y1