Dataguard, documentation/scripts for non-DBAs during failover
Posted on 2007-05-23
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:
Application/Business logic 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).