Designing Disaster Recovery Clusters using Metroclusters and Continentalclusters, Reprinted October 2011 (5900-1881)

PSUS(SSWS). During this transition, horctakeover will
attempt to flush any data in the side file on the MCU to the
RCU. Data that does not make it to the RCU will be stored
on the bit map of the MCU. When failing back to the
primary site any data that was in the MCU side file that is
now stored on the bit map will be lost during
resynchronization.
In synchronous mode with fence level NEVER, when the
Continuous Access link fails, the application continues
running and writing data to the PVOL. At this point the SVOL
contains non-current data. If there is another failure that
causes the package to fail over and start on the secondary
site, the PVOL will become PSUE and the SVOL will become
PSUS(SSWS). When failing back to the primary site, any
differential data that was on the PVOL prior to failover will
be lost during resynchronization.
NOTE: This variable is also used for the combination of
PVOL_PFUS and SVOL_PSUS. When either the side file or
journal volumes have reached threshold timeout, the PVOL
will become PFUS. If there is a Continuous Access link, or
some other hardware failure, and we fail over the secondary
site, the SVOL will become PSUS(SSWS) but the PVOL will
remain PFUS. Once the hardware failure has been fixed,
any data that is on the MCU bit map will be lost during
resynchronization. This variable will allow package startup
if changed from default value of 0 to 1.
If the package has been configured for a three data center
(3DC) environment, this parameter is applicable only when
the package is attempting to start up in either the primary
(DC1) or secondary (DC2) data center. This parameter is
not relevant in (the third data center) in the recovery cluster.
Use this parameter’s default value in the third data center.
Values:
0 – (DEFAULT) Do NOT failback to the PVOL side after an
outage to the PVOL side has been fixed. This will protect
any data that may have been in the MCU side file or
differential data in the PVOL when the outage occurred.
1–Allow the package to startup on the PVOL side. We failed
over to the secondary (SVOL) side due to an error state on
the primary (PVOL) side. Now we're ready to failback to
the primary side. The delta data between the MCU and
RCU will be resynchronized. This resynchronization will over
write any data that was in the MCU prior to the primary
(PVOL) side failure.
AUTO_PSUSSSWS (Default = 0)
This parameter applies when the PVOL is in the suspended
state PSUS, and SVOL is in the failover state PSUS(SSWS).
When the PVOL and SVOL are in these states, it is hard to
tell which side has the good latest data. When starting the
package in this state on the PVOL side, you run the risk of
losing any changed data in the PVOL.
Values:
0 – (Default) Do NOT startup the package at the primary
site. Require user intervention to choose which side has the
good data and resynchronizing the PVOL and SVOL or force
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