Hi all,

We currently have the following scenario:

[Oracle DB] <DBMLSync> [ASA] <Mobilink Sync> [Ultralite PDA]

The Oracle database hosts the main application and the ASA database is
loosely coupled with the Oracle database and receives all the jobs in a
DBMLSync. The Oracle database can go offline without it affecting the
mobile engineers.

Ok, now assuming we are on the latest version of Oracle and the latest
version of Sybase SQL Anywhere......

We need to add a failover site which has the same configuration.

NetApp is used to maintain changes from the Oracle database and apply the
changes to the failover site.
We setup the SQL Anywhere component to replicate and use the arbiter to keep
the failover SQL Anywhere database up to speed.

We then failover. The external IP is redirected so that it points to the
failover site so that the PDAs can still reach it.

Can we:
1) Start up DBMLSync on the failover SQL Anywhere database and get it
synchronising with the failover Oracle database?
2) Will the PDAs synchronise okay with the failover SQL Anywhere database?

Cheers,

Shao

Hi Shao,

Shao Chan wrote:
I have a few questions:

- What are you planning to do with the ASA server in the middle? Is it
also being "failed-over" in any fashion? Or is staying the same?

- Will the MobiLink server (in between Oracle and ASA) be aware of when
the Oracle server switches over? Or is there a separate MobiLink server
running against the failover Oracle server?

- Will the Oracle failover database be guanrateed to be"up-to-date" at
the time of the failover?

---

In general, the ASA database in the middle has to maintain both its
client status to Oracle (which is fine if it doesn't synchronize for a
bit during the failover period - it is the MobiLink *server* that it
talks to afterwards that has to keep track of where the "active" Oracle
consolidated server is) and its consolidated status with the UltraLite
remotes. If you just switch to a different ASA database which isn't a
mirror of the original ASA database at the time of the failover, it
won't know anything about the UltraLite remotes that have been
synchronizing and you will likely receive progress mismatch messages
trying to synchronize those.

All that would really be required to failover (just) the Oracle server
would be to either:

- Inform the original MobiLink server there has been a failover, by
restarting the server with a new DSN configuration for Oracle. This may
even be handled directly by the Oracle client configuration information
automatically without restarting - consult your local Oracle DBA for
details - I'm not one of them.

- Run a secondary MobiLink server against the failover Oracle server,
and re-route traffic to the secondary ML server, either by networking
configurations or by changing the dbmlsync "ADR" information by either
the "-e" switch or updating the synchronization subscription.

Regards,

--
Jeff Albion, Sybase iAnywhere

iAnywhere Developer Community :
http://www.sybase.com/developer/libr...ere-techcorner
iAnywhere Documentation : http://www.ianywhere.com/developer/product_manuals
SQL Anywhere Patches and EBFs :
http://downloads.sybase.com/swd/summ...&timeframe =0
Report a Bug/Open a Case : http://case-express.sybase.com/cx/

Hi Jeff,

Thanks for the response.

The scenario is if the primary site gets bombed and is no longer available
ever.

The ASA is being failed over.

No, but we can have manual processes in place to start the second Mobilink
at the DR site.

At the moment, 'No' but it will soon be a 'Yes' and that is what I am
working towards. It would not be fair to assume that Mobilink could cope
with an old snapshot of the Oracle database.

Essentially we want to be able to say that the iAnywhere database replicates
and then when failing over, provided that the Oracle database is identical
in the DR site, that starting DBMLSync at the DR site will work.

The same needs to apply with the mobile PDAs changing to synchronising with
the DR site.

Thanks.

Shao


"Jeff Albion [Sybase iAnywhere]" <firstname.lastname (AT) ianywhere (DOT) com> wrote in
message news:4afc850d$1 (AT) forums-1-dub (DOT) ..