HP P6000 Replication Solutions Manager User Guide (T3680-96089, October 2012)

Default setting and user control
• When a DR group pair is created, Failsafe on link-down/power-up (presentation blocking) is
enabled by default.
• After a DR group pair is created, some versions of controller software allow you to change
the failsafe on link-down/power-up setting. In other versions, the setting cannot be changed.
See Page 238.
Failsafe on unavailable member
Failsafe on unavailable member is a data protection feature that specifies how host-writes, logging,
and remote replication occur when a component in the DR pair becomes unavailable during normal
power-on operation. Values are:
• Enabled
While all components in the DR group pair function normally, host writes, logging, and
remote replication continue normally.
◦
◦ When any virtual disk in the DR group pair becomes unavailable, host writes, logging,
and remote replication are stopped.
• Disabled
While all components in the DR group pair function normally, host writes, logging, and
remote replication continue normally.
◦
◦ If any remote copy (virtual disk) in the DR group pair becomes unavailable, all host writes
to the source DR group and logging continue, but remote replication to the destination
DR group is automatically stoped. Host writes are stored in the source DR group log until
remote replication is re-established.
◦ If a source virtual disk becomes unavailable, host writes to the virtual disk are automatically
stopped. Remote replication to the remote copy is also automatically stopped. Host writes,
logging, and remote replication to other virtual disks in the source and destination DR
groups continue normally.
Default setting and user control
When you create a DR group pair, you can choose to initially enable or disable the feature. The
setting can be changed after the DR group pair is created.
In some older versions of storage management software, failsafe on unavailable member is called
failsafe mode. See also Failsafe states, Remote replication guidelines, and Failsafe on
link-down/power-up.
Failsafe states
The failsafe state for a DR group pair indicates the state of host I/O, logging, and remote replication
functions. Values are:
• Locked. A locked failsafe state for a DR group pair indicates that host writes, logging, and
remote replication have been automatically stopped due to a problem.
• Unlocked. An unlocked failsafe state for a DR group pair indicates that host writes, logging,
and remote replication are occurring normally.
Failsafe states are related to settings for Failsafe on link-down/power-up and Failsafe on unavailable
member.
DR group concepts 83