Building Disaster Recovery Serviceguard Solutions Using Metrocluster with Continuous Access for P9000 and XP A.11.00

RCU. Data that does not make it to the RCU is 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 is 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 becomes PSUE and the SVOL becomes
PSUS(SSWS). When failing back to the primary site, any
differential data that was on the PVOL before to failover is
lost during resynchronization.
NOTE: This variable is also used for the combination of
PVOL_PFUS and SVOL_PSUS. When the side file or journal
volumes reach threshold timeout, the PVOL becomes PFUS.
If there is a Continuous Access link, or some other hardware
failure, and we fail over the secondary site, the SVOL
becomes PSUS(SSWS) but the PVOL will remain PFUS. Once
the hardware failure is fixed, any data that is on the MCU
bit map is lost during resynchronization. This variable allows
package startup if changed from default value of 0 to 1.
If the package is 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 protects any
data that might 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 is
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
the package to start by creating the FORCEFLAG file.
1—Startup the package after resynchronize the data from
the SVOL side to the PVOL side. The risk of using this option
is that the SVOL data might not be a preferable one.
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