Little things worth knowing: when a transient ASM disk failure cannot be fixed in time

In the previous blog post I used libvirt and KVM in my lab environment to simulate a transient disk failure and how to recover from it. This post takes this example a step further: I am simulating another disk failure, but this time won’t pretend I can fix the issue and put it back. In other words, I simulate the effect of the disk_repair_time hitting zero.

Most of what I am covering here is an (more...)

Little things worth knowing: transient ASM disk failures in 12c

For quite some time we have been treated nicely by ASM when it comes to transient disk failures. Since 11.1 (if memory serves me right), transient failures won’t cause an ASM disk to be dropped immediately. This is good, because it can potentially save a lot of time! When a disk is dropped from an ASM disk, a rebalance operation is unavoidable. And there is more than a chance of another one following it, (more...)

Comparing workloads across databases

Does this question sound familiar? “We are running the exact same workload in UAT as we do in production, but it behaves completely different. Can you help?”

If it does, then you might find the following post useful, provided you are appropriately licensed to use this feature anyway. I have been working on AWR data for a long time, and one of the best ways to do so according to David Kurtz and others, (more...)

Little things worth knowing: using Remote Diagnostic Agent more effectively with profiles

RDA, or the Remote Diagnostics Agent, has been around for a little while. Over the time, and with the growing number of Oracle’s acquisitions it has become, shall we say, a little more difficult to handle. It appears to me as if every one of them will have its diagnostics handled by RDA making it hard to focus on something specific, like for example the database.

I won’t go into very detail of the Remote (more...)

OSWatcher integration in Trace File Analyzer (TFA)

Some time ago I wrote a post about using OSWatcher for system analysis. Neil Chandler (@ChandlerDBA) rightfully pointed out that although OSWatcher was cool, TFA was the way to go. TFA can include OSWatcher, but more importantly it adds a lot of value over and above what OSWatcher does.

I guess it depends on what you want to do-I still think that OSWatcher is a good starting point and enough for most problems on single (more...)

Preventing a SPOF with CMAN 12c

I have already written about the use of Connection Manager 11.2 to govern access to a database. While researching this piece I have updated the original post so that it’s relevant for 12c as well.

Although the idea of using Connection Manager is tempting, the obvious first question is about high availability of the process. After all, if the gatekeeper to your database environment fails, you are effectively closed for business. One option would (more...)

Tales from the field: potential reasons for PDB plug-in violations part 2

In the first part of this little series I explained how a missing (default) tablespace in a PDB can have an impact when opening it. In this instalment I’ll add another common cause for PDBs not opening in read-write mode: different patch levels between the PDB to be plugged in and the CDB.


Assume for a moment that you upgraded Oracle binaries from to (more...)

Tales from the field: potential reasons for PDB plug-in violations part 1

Container Databases have been an area that I have researched intensively over the past years. With this post (and hopefully some others that follow) I would like to demonstrate some of the new situations the DBA might be confronted with. Please don’t use this post to give the new 12c architecture a hard time: standardised deployments (which I love) help you a lot. Not only do your DBA scripts work reliably everywhere, but the error condition (more...)

Automatic Deployment of CDBs with non-default database options in

I have written about the importance of automation in previous posts, and this one is following the same line. This time I wanted to test and document my experience with “golden database templates”. Wy? Because most DBAs will appreciate that there are more interesting things to do than to run “create database” scripts all day, so why not automate the process? For quite some time DBCA, or the Database Creation Assistant offers you the option (more...)

Using OSWatcher for system diagnostics

OSWatcher is a superb tool that gathers information about your system in the background and stores it in an (optionally compressed) archive directory. As an Oracle DBA I like the analogy with statspack: you make the tool available on the host in a location with – very important – enough available disk space and then start it. Most users add it to the startup mechanism their O/S uses- SysV init, upstart, or systemd for example (more...)