Understanding host error recovery procedures outlines the actions that the host ERP starts
when a PPRC duplex pair fails. It is possible that PPRC links fail
such that the secondary device’s storage control does not receive
notices that the duplex volume is in suspended state. In this case,
the primary host ERP issues an IEA49xx message.
The host ERP action waits until the message is issued before allowing
the primary application to continue. This delay gives an automation
product such as NetView® time
to locate the IEA49xx message and automatically
take appropriate actions.
In the event of a disaster, these actions provide data that is
necessary to analyze the PPRC secondary volume to determine how current
the data is. See
Putting PPRC error recovery procedures into effect to decide which recovery actions
to take. These recovery actions can include the following:
- Locate the IEA49xx message via NetView and copy the message
to the recovery system, thereby informing the recovery system that
the PPRC duplex pair is in suspended state. The message contains the
timestamp that indicates the time that the pair became suspended.
- Locate the IEA49xx message via NetView. Next, issue a CSUSPEND
command from either host to the secondary device’s subsystem to
notify the storage control that the PPRC pair is in suspended state.
The recovery subsystem records the suspension time.