Increase disk space for VM running Linux

When I create virtual machines on my notebook I always create too small disk for root partition or partition where I put Oracle binaries. After a while when I want to perform upgrade, or install another Oracle software, there is not enough space. This time I want to note steps about how to increase disk free space.

I can easily extend or shrink my logical volumes because I am using LVM in my virtual machines. (more...)

Using Oracle Flex ASM with single instance database

Oracle Flex ASM was introduced in 12c version. This is one of the best features introduced with new version in my opinion.

I won’t speak in detail about Flex ASM because you can find more information in documentation. In this post I will concentrate on how Flex ASM handles crash of ASM instance.

For this test I’ve created 2 node cluster - 12c Grid Infrastructure with Flex ASM enabled.

$ asmcmd showclustermode
ASM cluster : (more...)

ORA-19909: datafile 1 belongs to an orphan incarnation

I love to read Oracle related blogs, forum posts and mailing lists much more often than books. Why? Because there many Oracle DBA’s and developers share their experiences, problems, "best practices",... which are very valuable to me.

It's great that we have so big and active Oracle community.

Today I noticed mail from Oracle-L list where someone asked for help with recovery after overwriting production controlfiles. Check Oracle-L for more info.

It reminded me that (more...)


I've played a little with Oracle SQL Plan Management and something caught my eye.

Let's create simple test.

SQL> select /* test_spm */ count(*) from admin.objekti;


SQL> set lines 200
SQL> col sql_text for a50 wrapped
SQL> select sql_id, sql_text from v$sql
2 where sql_text like '%test_spm%';

------------- --------------------------------------------------
cpzgdw9swdvzk select /* test_spm */ count(*) from admin.objekti
ap9td7vafq26n select sql_id, sql_text from v$sql where sql_text
like '%test_spm%'

I (more...)

RAC One Node 12cR1 Instance placement after failover

RAC One Node is Oracle active-passive solution very similar to RAC which is active-active solution.
Running active-passive solution using Oracle Clusterware was possible even before introduction of RAC One Node, but RAC One node brought configuration and managing of active-passive cluster to another level.

In my test environment I've created active-passive cluster using 12cR1 Grid Infrastructure with 12cR1 RAC One Node database.

I've tested failover for Oracle database and noticed interesting behavior with instance placement.