NetBase for MPE Reference Guide

Chapter 5
5-58
Shadowing with Dynamic Rollback Recovery
Note. The following procedures must be followed if 1) you are shadowing a
TurboIMAGE and not using TPS, and 2) if the application on the master system uses
DBXBEGIN, DBXEND and DBXUNDO.
If the application on the master system uses the DBXBEGIN, DBXEND and DBXUNDO TurboIMAGE
intrinsics, the ;DBX option must be used to ensure the database stays in sync. The ;DBX option is
specified on the SHADOW statement on the shadow system. See the steps below for setting up
shadowing with this option.
Warning! Do not use this parameter on databases that do not use dynamic rollback, since
there is a performance hit on the shadowing side.
To shadow with dynamic rollback recovery:
1. Your SHADOW statement on the shadow machine needs to have DBX added to it, for example:
SHADOW CHKDB.group.account;PASS=TALK;DBX
2. The Enable Critical flag must be set on the master machine. To check if this is set, do the
following:
:RUN NBCTRL.PUB.NETBASE
>SHOW SERVICES
If the following line is present, this flag is already set:
CRIT UPDATE: ENABLED
If the following line says:
CRIT UPDATE: DISABLED
then you need to issue the following command:
>ENABLE CRITICAL