RE: Remote Journaling

There are two modes of operation for remote journalling - asynchronous
maintenance and synchronous maintenance.

I am clipping here excerpt from the Backup and Recovery book :

Asynchronously             ¦  This describes a remote journal
maintained                   ¦ function delivery mode for
                                   ¦ journal entry replication where
                                   ¦ control is returned to the
                                   ¦ application generating the
                                   ¦ journal entry on the source
                                   ¦ system without waiting for the
                                   ¦ journal entry to be replicated to
                                   ¦ the remote journal. An
                                   ¦ asynchronously maintained remote
                                   ¦ journal may lag several journal
                                   ¦ entries behind the total number
                                   ¦ of journal entries in the journal
                                   ¦ on the source system.
                                   ¦
                                   ¦ Contrast with synchronously
                                   ¦ maintained.

 Synchronously             ¦ This describes a remote journal
 maintained                   ¦ function delivery mode for
                                    ¦ journal entry replication where
                                    ¦ control is not returned to the
                                    ¦ application generating the
                                    ¦ journal entry on the local system
                                    ¦ until the journal entry is
                                    ¦ replicated to the remote journal.
                                    ¦
                                    ¦ Contrast with asynchronously
                                    ¦ maintained.

Another question is whether placing entries to journal (receiver) is
performed asynchronous or synchronous to application operations.
If you have journalling but no commitment control, journal operations
will be synchronous. If you use commitment control, then they will be
asynchronous and synchronization points will be COMMIT or ROLLBACK
operations.

I believe it will also work the same for remote journalling.


    Best regards,

          Alexei Pytel



> -----Original Message-----
> From: Kenneth E. Graap [SMTP:keg@nwnatural.com]
> Sent: Wednesday, November 04, 1998 1:17 PM
> To:   MIDRANGE-L@midrange.com
> Subject:      Remote Journaling
> 
> 
> Hello
> 
> I am thinking about implementing remote journaling soon.
> 
> I have one concern though...
> 
> When a journal entry is made into a remote journal, does it slow down
> the job
> running at all. I've been told that the job waits until the remote
> system
> acknowledges receipt of the journal entry....
> 
> However, it has always been my understanding that journal entries run
> asyncronously to the application making the file updates... If this is
> true then
> the application making the file updates should not be affected at all.
> 
> thanx in advance for your comments
> 
> Kenneth Graap
> NW Natural Gas
> keg@nwnatural.com
> Portland, OR....
> 
> Currently in Atlanta at the IBM Technical Conference!
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