Sep 18 2020

After Revoked Tablespace Quota From User in Oracle

In topic, I will descript how Oracle handle once we revoke tablespace quota from user. Once blocks assigned to a segment, even after revoked the Tablespace quota and deleted records from table, all allocated block will remain mapping with segment until we released block by using Shrink.
This is the one good reason to release the space once we delete lots of records from a segment.

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Sep 02 2020

Unused or Drop Column? Which option should use?

Sometimes DBA got request to drop the table’s columns. Oracle has following options to complete this task.

In this article, I will discuss which option is more appropriate for big size of table. For small table, even physical delete will not take take much time or resource.

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Sep 01 2020

Oracle RAC Cache Fusion

Until Oracle 8i released, Oracle Introduced Parallel Server on Oracle 6i version. Oracle Introduced Real Application Cluster concept on Oracle 8i version. Oracle Cache Fusion is one of the important component in Oracle RAC environment.

What is Cache Fusion:

Oracle RAC has two or more instances, and it uses Cache Fusion to smoothly move data blocks between these instances’ buffers across the cluster connection. If one instance reads a data block from the disk and another instance needs the same block, it’s faster to grab it from the instance that already has it in its memory (SGA) than reading from the disk again. This quick transfer across the network is way faster than dealing with the slower disk operations, making Oracle RAC work better.

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Aug 30 2020

Oracle Database 19c Installation On Oracle Linux 7.1

I will describe the installation process of Oracle 19c (19.3) Database on Oracle Linux 7.1 on VM.

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Aug 24 2020

How to Rename Ethernet Interface to eth0 in Linux on VM

Sometime you may need to change the Network Interface Name on your system. I faced issue while I was cloning a node to prepare a new node for RAC Environments on Oracle Linux 6.5.

When you clone a VM, you need to reassign the Network device means it will assign new UUID for the device and it will create new Network Interface at OS level. But For RAC, You need to set same name of Network Interface for all nodes. I got below error while was trying install GI (Grid Infrastructure) with different Network Interface Name.

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Aug 18 2020

Copy Password File From Primary ASM to Standby ASM on Oracle 12c

If create a database using DBCA, usually password file create on ASM Diskgroup. For RAC, this is also recommended to use ASM Diskgroup for spfile and password file. In this topic, I will show how to copy password file from ASM of Primary database to Standby on ASM.

Password File location on Primary Database:

[oracle@ocmnode1 ~]$ . oraenv
ORACLE_SID = [ORCL1] ? +ASM1

[oracle@ocmnode1 ~]$ asmcmd pwget --dbuniquename ORCL
+DATA/ORCL/PASSWORD/pwdorcl.256.1048094823
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Aug 13 2020

Unable To Load Module Oracleasm in Oracle 12c

CRS (Cluster Ready Service) is not starting and getting ‘FATAL: Module oracleasm not found’ error on log files.

[root@ocmnode1 ~]# cat /var/log/messages

Aug 12 01:32:08 ocmnode1 modprobe: FATAL: Module oracleasm not found.
Aug 12 01:32:33 ocmnode1 modprobe: FATAL: Module oracleasm not found.
Aug 12 01:34:32 ocmnode1 modprobe: FATAL: Module oracleasm not found.

After checked in details found that oracleasm package / RPM was not working. 

[root@ocmnode1 ~]# oracleasm init
Creating /dev/oracleasm mount point: /dev/oracleasm
Loading module "oracleasm": failed
Unable to load module "oracleasm"
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Aug 09 2020

Migrating OCR, Voting Disk and MGMTDB to another ASM DiskGroup in 12c RAC

Sometime DBA need to move or migrate below mentioned files or DB to different ASM DiskGroup for difference reason. I will show how to move or migrate below mentioned files or DB from one ASM DiskGroup to Another:

  • How to move or migrate OCR and Voting Disk from one ASM Diskgroup to another.
  • How to move or migrate SPFILE and PWDFILE from one ASM Diskgroup to another.
  • How to move or migrate MGMTDB from one ASM Diskgroup to another.
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Aug 08 2020

Adding a Node to Oracle RAC 12c

Complete below list of tasks:

DBA may need to add a new node or existing node (which got deleted from cluster) into Clusterware.

List of tasks for New Node:

  • Install same version of OS
  • Setup environment variable
  • Install all required package including Oracleasm
  • Configure Networking (IP and others)
  • Check Time Synchronization 
  • Change Recommended Kernel Parameters for Oracle
  • Create Group and User (make sure these are same with existing Nodes)
  • Setup SSH configuration for grid user or (user which was used for GRID installation) between new node and other nodes.
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Aug 01 2020

Deleting a Node to Oracle RAC 12c

A node in the cluster may crash due to hardware or OS problems and is not recoverable. So DBA needs to delete a problematic node from clusterware. In this topic I will show discuss how to delete a node from two nodes RAC.

Two Nodes: ocmnode1 will be deleted

  • ocmnode1
  • ocmnode2

Deinstall Oracle Home:

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