On Wed, Jul 17, 2013 at 3:50 PM, Robert A. Rosenberg <[email protected]> wrote:
> At 12:42 -0500 on 07/17/2013, Joel C. Ewing wrote about Re: Old usercatalogs
> with EMBED and REPLICATE:
>
>> Not sure about rules in multi-system environment, but with one system I
>> believe it was possible to DIAGNOSE a catalog to be sure no serious
>> problems  existed, LOCK it, backup, redefine, restore/reorganize, UNLOCK
>> while system was running and datasets in the catalog were OPEN and in
>> use.  As long as you could tolerate short-term inability to OPEN/CLOSE
>> any datasets in the catalog, it was sometimes possible to move or
>> rebuild a catalog with in-use datasets without disrupting critical loads
>> - although admittedly this assumes you have enough control over or
>> knowledge about the loads and datasets involved to make that assessment.
>>  One just had to be sure the batch jobs doing the work and TSO user
>> controlling the process were designed to have no requirements for
>> OPEN/CLOSE of datasets in the catalog
>
>
> Being unable to OPEN/CLOSE is only the tip of the Iceberg. You can not do
> any CI or CA splits either since the backup and reorg will be out of sync
> with the updates. Only if every dataset in the catalog is read-only can you
> get away with  doing what you are talking about. Even then I have a gut
> feeling you can run into problems with the in memory status being out of
> sync with the new locations of the catalog records.
>
That is what the LOCK does.  Any task that goes to update the catalog
is held until the catalog is UNLOCKED.  This can result in hung
applications, etc.

-- 
Mike A Schwab, Springfield IL USA
Where do Forest Rangers go to get away from it all?

----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [email protected] with the message: INFO IBM-MAIN

Reply via email to