Hello everyone,
I received some information back from IBM.

*If data loss cannot be tolerated at the DR site, STG_DUPLEX in the
LOGSTREAM definition must be set as YES.*
*CICS cannot tolerate LOGSTREAM data loss.*

Just sharing information here, in case someone runs into a similar
situation in the future.

On Wed, Aug 28, 2019 at 7:34 PM Cameron Conacher <[email protected]> wrote:

> Hello folks,
> I have a question and precious little information.
> We use CDC IIDR to support replicating VSAM file updates downstream from
> our CIC applications.
>
> We have a LOGSTREAM defined in the Coupling Facility of our SYSPLEX.
> Apparently, there is a VSAM file that is defined behind the CF LOGSTREAM.
> I know very little about this. We simply requested the LOGSTREAM to be
> made available to our CICS Regions, and our IBM resources waved their magic
> wands and it was there.
>
> Anyway, I pro-actively defined all LOGSTREAMs that we would be requiring
> for production, well ahead of when we would actually require them.
>
> Sometime later but before we installed out application change we ran a
> Disaster Recovery test event.
> When the DR event ran, there was a hiccup with our LOGSTREAM.
> Sadly no diagnostic information was collected and saved.
> I had our IBM folks redefine the LOGSTREAM and we were back in business.
>
> So, I now have a couple of questions for anyone that can help me
> understand things.
>
> At the time CF structures are defined, is the VSAM file also automatically
> defined?
> Are these two separate/distinct steps?
>
> When Coupling Facility structures are defined, would this definition be
> part a "normal" mirroring process that manages DR?
> Is the LOGSTREAM something special I should call out to IBM to indicate it
> requires DR attention?
> Assuming that file systems are mirrored even for the CF, would data in the
> LOGSTREAM VSAM file be mirrored to the DR site?
> Would it make any difference if the VSAM file were never used, and
> therefore present as an unloaded (never used) VSAM file?
> I assume that a never used VSAM file would have nothing mirrored to the DR
> site.
> Would that present any difficulties to starting the DR site?
> Maybe the VSAM file is automatically defined for the LOGSTREAM at SYSPLEX
> startup time, if none is available from the catalog?
> But if one is available in the catalog, maybe it cannot be in an unloaded
> state at SYSPLEX startup time?
>
> Anyway I would appreciate any information anyone might share. I am just
> curious about this at the moment.
> I do not have a burning problem. I would simply like to understand a bit
> better.
>
> Thanks
>
>

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