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Showing posts from June, 2011

Troubleshooting RAC Public Network Failure

Here are some steps I used to troubleshoot the failure of a public network used for SCAN in a 2-node RAC cluster.
Note: I used an aliased crsstat  for the command: crsctl stat res –t Check the status of the Clusterware resources. You can see that there are several resources that are offline below. The ones highlighted in red are the ones we are interested in. The resource for the local listener is now offline while the VIP has been failed over. You will also notice that all of the SCAN Listeners have been failed over to the surviving node. grid@tibora30[+ASM1]-/u01/11.2.0/grid/log/tibora30 >crsstat
--------------------------------------------------------------------------------
NAME           TARGET  STATE        SERVER                   STATE_DETAILS
--------------------------------------------------------------------------------
Local Resources
--------------------------------------------------------------------------------
ora.DG_DATA.dg
               ONLINE  ONLINE       tibora30
       …

Cloudy With a Chance of Database: Part I

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There has been a lot of talk in the ubiquitous cloud space recently and more specifically the PaaS service delivery model. Naturally this piqued my curiosity. How does the database fit in the cloud? Just about every major enterprise vendor is jumping on the cloud bandwagon. And rightfully so. Private clouds are now being pushed by Oracle with Exalogic Elastic Cloud and Exadata, IBM with SmartCloud and VMware with Cloud Foundry just to mention a few. Amazon AWS and Rackspace are the major players in the public cloud stratosphere. Add to this community Clouds like OpenStack
The easiest to do an evaluation is by using Amazon AWS public cloud services. Amazon AWS provides Relational Database Service (RDS) for MySQL and Oracle Database 11g. Strictly speaking EC2 is a Infrastructure as a Service (IaaS) delivery model. However, the use of AMIs enable PaaS characteristics where complete environments can be easily packaged and deployed in EC2. There are several publicly available Oracle Database …

ORA-00020: maximum number of processes (%s) exceeded

Ever received this error message in your alert log? I have on a couple of occasions. Perhaps an application server started spawning more database connections than it normally does in turn creating more processes on the database. The Oracle description of this error is:
Error: ORA 20 Text: maximum number of processes exceeded  Cause: An operation requested a resource that was unavailable. The maximum number of processes is specified by the initialization parameter PROCESSES. When this maximum is reached, no more requests are processed. Action: Try the operation again in a few minutes. If this message occurs often, shut down Oracle, increase the PROCESSES parameter in the initialization parameter file, and restart Oracle.
But what if you cannot connect to your database to shut it down and increase the parameter?

oradba01t[labdb01]-/home/oracle/>sqlplus  /as sysdba SQL*Plus: Release 11.1.0.7.0 - Production on Mon Jun 6 11:25:05 2011 Copyright (c) 1982, 2008, Oracle.  All rights reserved. ER…