Martins Blog

Trying to explain complex things in simple terms

Archive for January, 2011

Viewing Runtime Load Balancing Events

Posted by Martin Bach on January 20, 2011

Yesterday I have run a benchmark on a 2 node RAC cluster (ProLiant BL685c G6 with 4 Six-Core AMD Opteron 8431) and 32G RAM each. It’s running Oracle Grid Infrastructure as well as an Oracle database on Oracle Enterprise Linux 5.5 64bit and device-mapper-multipath.

I was testing how the system would react under load but also wanted to see if the Runtime Load Balancing was working. The easiest way to check this is to view the AQ events that are generated for a service if AQ HA notifications is set to true. They can either be dequeued from the database as described in chapter 11 of Pro Oracle Database 11g RAC on Linux or alternatively queried from the database. The latter is the quicker method and this article will focus on it.

Before you can make use of Runtime Load Balancing you need to set at least 2 properties in your service:

  • Connection Load Balancing Goal (either SHORT or LONG)
  • Runtime Load Balancing Goal (SERVICE_TIME or THROUGHPUT)

.Net applications require AQ HA notifications to be set to true as these can’t directly make use of Fast Application Notification (FAN) events as said in the introduction. My JDBC application is fully capable of using the FAN events, however as you will see later I am using the AQ notifications anyway to view the events.

Read the rest of this entry »

Posted in 11g Release 2, Linux, Performance, RAC | Leave a Comment »

Adding storage dynamically to ASM on Linux

Posted by Martin Bach on January 14, 2011

Note: This discussion is potentially relevant only to OEL 5.x and RHEL 5.x- I haven’t been able to verify that it works the same way on other Linux distributions. I would assume so though. Before starting with the article, here are some facts:

  • OEL/RHEL 5.5 64bit
  • Oracle
  • native multipathing: device-mapper-multipath

The question I have asked myself many times is: how can I dynamically add a LUN to ASM without having to stop any component of the stack? Mocking “reboot-me” OS’s like Windows I soon was quiet when it came to discussing the addition of a LUN to ASM on Linux. Today I learned how to do this, by piecing together information I got from Angus Thomas, a great Red Hat system administrator I had the pleassure to work with in 2009 and 2010. And since I have a short lived memory I decided to write it down.

I’ll describe the process from the top to bottom, from the addition of the LUN to the server all the way up to the addition of the ASM disk to the disk group. Read the rest of this entry »

Posted in 11g Release 1, 11g Release 2, Linux, RAC | 10 Comments »

Nice surprise-automatic statistics email

Posted by Martin Bach on January 2, 2011

Today I got a nice surprise email from WordPress. Seems like my blog wasn’t doing too badly last year. I would like to thank all visitors for passing by and reading my ramblings about this and that-mainly Oracle related.

Have a happy New Year all!

Posted in Uncategorized | Leave a Comment »