Oracle Flex ASM

Starting 12c, Oracle has introduced two very interesting features to add up to MAA (Maximum Availability Architecture), Oracle Flex Cluster and Oracle Flex ASM. In this article I will be explaining and demonstrating about Oracle flex ASM.

In flex ASM, you don’t need ASM instance to be running on each node (the Hub Node) because database instance can communicate with some other ASM instance running on any other node in the cluster.

Oracle Patches Types

In Oracle, there are different types of patching available; there are several types of patches released by Oracle that could be applied to the software you are running. There are on-off patches to fix bugs, regularly released patches, and security patches. In the following I will explain about different types of patches that are available to be installed on your RDBMS software.

Installing Oracle 12c Release 2 RAC on Linux 6 and Linux 7

This article explains how to install a 2 nodes Oracle 12c Release 2 Real Application Cluster (RAC) on Oracle Linux 6 and 7. I did this installation on Oracle Virtual Box by creating 2 virtual machines with shared storage. OS platform I used is Oracle Enterprise Linux 7, and Oracle GI and RDBMS version is 12.2. Same installation guide should work for Linux 6 also as there are only a couple of differences in the steps that I will explain during this installation. There will be no difference in installation steps if there are more than 2 nodes in the RAC setup.

Running cluvfy (Cluster Verification Utility) during 12c R2 RAC installation

Following is the output of cluster verification utility that I executed during 12c R2 RAC installation. You can see 2 examples in the following. Example 1 demonstrated if you don’t have passwordless SSH connectivity configured for “grid” and “oracle” users, so you will need to execute this from each node one by one. Following output is from one node only.

Creating Oracle Database using DBCA in 12c R2

Database Configuration Assistant (dbca) is an Oracle provided tool to create a new database. In this document I would explain how to create a new 12cR1 database using dbca. For database creation steps for Oracle 12cR1, follow this document. Steps and screens are almost same for other Oracle database versions and different OS platforms.

Creating ASM disks using ASM Filter Driver (ASMFD)

Starting 12.1.0.2 we can use ASM Filter Drive (ASMFD) to create ASM disks to be used for ASM diskgroups. I have already explain in this article that how we configure ASMFD during GI installation, and this article for migration from ASMLib to ASMFD. In this article I will show you how to create/add new ASM disks using ASMFD so that we can use them for existing or new diskgroups.

ASMCMD-9524: AFD configuration failed 'ERROR: ASMLib deconfiguration failed'

While configuring ASMFD (ASM Filer Driver), I was playing around and started facing this error after issuing “afd_configure” command

[root@salman11 ~]# /u01/app/12.2.0/grid/bin/asmcmd afd_configure ASMCMD-9524: AFD configuration failed 'ERROR: ASMLib deconfiguration failed'

I simply stopped oracleasm and acfsload service and after that reissued the “afd_configure” command, and it started working fine.
Point to note is that we need to stop oracleasm and acfsload before configuring ASMFD using “afd_configure”.

Migrating from ASMLib to Oracle ASM Filter Driver (ASMFD)

Starting 12.1.0.2, ASMFD can be used instead of ASMLib for the ASM disks management. In this article I will explain how to migrate from ASMLib to ASMFD. I already have ASMLib configured on my server and I want to move to using ASMFD. For new GI installation, we can configure ASMFD for our ASM disks from GI installation wizard. Method explained here works for both standalone GI installations as well as for RAC.

Configuring Oracle ASM Filter Driver (ASMFD) and Labelling Disks

If you already have 12.2.0.1 and above GI/RAC installation and you want to migrate to ASMFD, click here.

Starting 12.2.0.1, downloaded Grid Infrastructure (GI) software zip is extracted directly in to the directly we have already chosen as ORACLE_HOME for GI. After extraction, we execute $ORACLE_HOME/gridSetup.sh script to initiate the setup wizard. If we want to use ASMFD (ASM Filter Driver), then after we have provisioned the disk/partition at OS level, we can configure ASMFD as follows. We no longer need ASMLib to setup ASM disks once we start using ASMFD.

Disabling Transparent Huge Pages on Linux 6 and Linux 7

Oracle recommends that Transparent Huge Pages should be disabled before installation of Oracle software. In the following I will explain how to disable Transparent Huge Pages on Linux 6 and Linux 7. I am using Oracle Enterprise Linux where I see that this feature is already disabled. You can check for your release of Linux whether it is disabled or not, and disable it using method explained here. This is the official document for doing this task.