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OOW14 Session: RAC'fying Multitenant

Thank you for attending my session RAC'fying Multitenant at Oracle Open World 2014. You can download the slide deck here.

[Updated] Oct 4th, 2014: The article on multitenant I wrote for OTN is available here. http://www.oracle.com/technetwork/articles/database/multitenant-part1-pdbs-2193987.html. This article shows various commands I referenced in my session, e.g. point in time recovery of PDBs.

As always I would love to hear from you.

OOW14 Session: Cache Fusion Demystified

Thank you all those who attended my session Cache Fusion Demystified.

As I mentioned, it was impossible to fit in a demo within that compressed 45 minute timeline. I put the details of the demo in a separate file with all the scripts and instructions that allows you to execute the demos at your own site.Download the slide deck as well as the scripts. In addition I have also written a whitepaper to explain the concepts clearer.

Download the slides, the paper, the demo scripts and instructions here.

I sincerely hope it demystified one of the most complex topics in Oracle RAC. As always, I would love to hear from you about your experience.

A first look at RAC 12c (part I)

I have recently upgraded my RAC 12.1.0.1.3 system to RAC 12.1.0.2 including the RDBMS installation. Currently I am updating my skills with information relevant to what I would normally have called 12c Release 2 (so that would also answer the question: when is 12c Release 2 coming out?). Then I realised I haven’t posted a first look at RAC 12c post yet-so here it comes.

There are a few things that aren’t specifically mentioned in the new features guide that caught my eye. First of all, RAC 12 does a few really cool things. Have a look at the srvctl command output:

Upgrading clustered Grid Infrastructure to 12.1.0.2 from 12.1.0.1.3

Oracle 12.1.0.2 is out, after lots of announcements the product has finally been released. I had just extended my 12.1.0.1.3 cluster to 3 nodes and was about to apply the July PSU when I saw the news. So why not try and upgrade to the brand new thing?

What struck me at first was the list of new features … Oracle’s patching strategy has really changed over time. I remember the days when Oracle didn’t usually add additional features into point releases. Have a look at the new 12.1.0.2 features and that would possibly qualify to be 12c Release 2…

In summary the upgrade process is actually remarkably simple, and hasn’t changed much since earlier versions of the software. Here are the steps in chronological order.

./runInstaller

I don’t know how often I have type ./ruinInstaller instead of runInstaller, but here you go. This is the first wizard screen after splash screen has disappeared.

HA of Database Control for RAC made easy

When you install an 11g RAC database without Grid Control respectively Cloud Control present, this is what the DBCA will give you:

RAC_dbconsole1There is one Database Control OC4J Container only, running on host01. Should host01 go down, the Enterprise Manager is no longer available now. We could make that a resource, known to the clusterware and let it failover in that case. But also – and even easier – we can start a second OC4J Container to run on host02 simultaneously like this:

RAC 12c enhancements: adding an additional SCAN-part 1

Based on customer request Oracle has added the functionality to add a second SCAN, completely independent of the SCAN defined/created during the cluster creation. Why would you want to use this feature? A few reasons that spring to mind are:

  • Consolidation: customers insist on using a different network
  • Separate network for Data Guard traffic

To demonstrate the concept I am going to show you in this blog post how I

  1. Add a new network resource
  2. Create new VIPs
  3. Add a new SCAN
  4. Add a new SCAN listener

It actually sounds more complex than it is, but I have a feeling I need to split this article in multiple parts as it’s far too long.

The lab setup

RAC 12c enhancements: adding an additional SCAN-part 1

Based on customer request Oracle has added the functionality to add a second SCAN, completely independent of the SCAN defined/created during the cluster creation. Why would you want to use this feature? A few reasons that spring to mind are:

  • Consolidation: customers insist on using a different network
  • Separate network for Data Guard traffic

To demonstrate the concept I am going to show you in this blog post how I

  1. Add a new network resource
  2. Create new VIPs
  3. Add a new SCAN
  4. Add a new SCAN listener

It actually sounds more complex than it is, but I have a feeling I need to split this article in multiple parts as it’s far too long.

The lab setup

Golden rules of RAC performance diagnostics

After collaborating with many performance engineers in a RAC database, I have come to realize that there are common pattern among the (mis)diagnosis. This blog about discussing those issues. I talked about this in Hotsos 2014 conference also.

Golden rules

Here are the golden rules of RAC performance diagnostics. These rules may not apply general RAC configuration issues though.

  1. Beware of top event tunnel vision
  2. Eliminate infrastructure as an issue
  3. Identify problem-inducing instance
  4. Review send-side metrics also
  5. Use histograms, not just averages

Looks like, this may be better read as a document. So, please use the pdf files of the presentation and a paper. Presentation slide #10 shows indepth coverage on gc buffer busy* wait events. I will try to blog about that slide later (hopefully).

Dynamic Resource Mastering in 12c

I blogged about Dynamic Resource Mastering (DRM) in RAC here . DRM freezes the global resources during the reconfiguration event and no new resources can be allocated during the reconfiguration. This freeze has a dramatic effect of inducing huge amount of waits for gc buffer busy [acquire|release] events and other gcs drm freeze release, gcs remaster events. In database version 12c, DRM has been improved further.

A major improvement I see is that not all resources are frozen at any time. Essentially, resources are broken down in to partitions and only a resource partition is frozen. This improvement should decrease the impact of DRM related waits tremendously.

LMON Trace file

Hotsos 2014

I will be presenting in HOTSOS symposium 2014 discussing correct methods to diagnose RAC performance issues. Very surprisingly, even very senior performance engineers make mistakes in their analysis while reviewing RAC issues. Come to my presentation and learn the golden rules of RAC performance diagnostics.