Dataguard, documentation/scripts for non-DBAs during failover
- From: "Stephen Booth" <stephenbooth.uk@xxxxxxxxx>
- To: freelists <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 23 May 2007 12:35:43 +0100
We're looking at implementing Dataguard as part of an implementation
of Documentum (a document management system from EMC) and I have been
asked to look at producing documentation and scripts for non-DBA users
to use during a failover. The actual failover of the database itself
will be handled by our DBAs, this is for the sys admins, network
admins, application admins &c who may need to do things during fail
over.
I'm currently going through the Dataguard concepts guide and have
found some other documentation on OTN but was hoping that someone with
more knowledge of Dataguard could point me towards any documentation
that might help with the non-Oracle side of failover. If anyone has
any documentation/scripts like this they have prepared themselves that
they are prepared to share and I could adapt to our environment then
I'd be very grateful.
Here is the background:
We have a pair of IBM p590 servers, currently sitting in different
parts of the same datacentre but (hopefully) one will be moving to a
different site in the near future. Each will run both primary and
standby environments, one running the standbys for the primaries on
the other. Each environment will run in a virtual server.
The Documentum service runs in an N-Tier configuration:
Presentation layer/
Application/Business logic layer
Metadata/Storage layer
The presentation layer is either a fat client running on local PCs or
a web front end running in Tomcat that the users can access via a
browser. The application/business logic layer is the Documentum
application running in Oracle Application Server 10g. The
metadata/storage layer consists of an Oracle 10g database and
filesystem storage on IBM storage devices.
Additionally on the application/business logic layer there are
interfaces to SAP provided by Documentum Services for SAP running on a
separate Windows 2003 server and scanning stations and servers, these
connect to the Documentum application.
Users do not access the database directly, nor do any other services,
all access is via the application.
When a document is added to the repository (via the presentation
layer, Services for SAP or scanned) it is rendered to PDF and added to
a filestore on the storage (i.e. the file is saved to a directory),
metadata about the document (title, location, categories, key words
&c) are stored in the Oracle database.
The filestore will be synced from primary to standby by either IBM
Flashcopy or IBM Metro Mirror, the metadata will be synced by Oracle
Dataguard. Due to the way Documentum handles inconsistency between
the metadata and the filestore (i.e. documents in one that are not in
the other) the metadata sync will always lag behind the filestore sync
(if there's metadata for a non-existant document then the metadata can
easily be found and deleted but if there's no metadata for an existing
document it's a bigger job to find the document, an analogy would be
looking up words in a book's index to find them in the book vs
checking each word in a book to see if it's in the index).
Stephen
--
It's better to ask a silly question than to make a silly assumption.
http://stephensorablog.blogspot.com/
http://www.linkedin.com/in/stephenboothuk
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