Oct 12 2017

Oracle 12c R2 (12.2.0.1) Real Time Apply Data Guard Installation on Oracle Linux 7.3

Category: Administration,Backup And RecoveryFatih Acar @ 11:11

Oracle Data Guard ensures high availability, data protection, and disaster recovery for enterprise data. Oracle Data Guard provides a comprehensive set of services that create, maintain, manage, and monitor one or more standby databases to enable production Oracle databases to survive disasters and data corruptions. Oracle Data Guard maintains these standby databases as copies of the production database.Then, if the production database becomes unavailable because of a planned or an unplanned outage, Oracle Data Guard can switch any standby database to the production role, minimizing the downtime associated with the outage. Oracle Data Guard can be used with traditional backup, restoration, and cluster techniques to provide a high level of data protection and data availability.

With Oracle Data Guard, administrators can optionally improve production database performance by offloading resource-intensive backup and reporting operations to standby systems.

Types of standby databases are Physical standby database, Logical standby database and Snapshot standby database.

I will demonstrate Physical standby database as working real time apply at this document. Most used type is Physical standby database type. You can investigate other types of standby database from Oracle docs.

I used Oracle RAC database as primary side and I used single instance database with asm file system as secondary side (Data Guard).

Firstly, you have to adjust system parameters of operating system on secondary side and create asm disks. After, you can start to install of grid infrastructure. You can create disk groups for DATA and FRA disk groups after install grid. After grid installation, you can install Oracle Data Guard database on grid infrastructure and ASM disks as software only. Finally you can restore and recover standby database from primary side and you can start synchronization apply after add standby redo log. I divide the stages of installation five steps.

You can find primary side (Oracle 12c RAC) installation steps here. I will use this infrastructure as primary side.

First Step : Configure Operation System on Secondery Side

1. Upgrade Packages

yum upgrade

yum install oracleasm-support

Continue reading “Oracle 12c R2 (12.2.0.1) Real Time Apply Data Guard Installation on Oracle Linux 7.3”

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Tags: Oracle 12c, Oracle Administration, Oracle Backup and Restore, Oracle Data Guard


Oct 10 2017

TNS-12547: TNS:lost contact and Linux Error: 32: Broken pipe While Connect Oracle 12c Data Guard

Category: Errors and SolutionsFatih Acar @ 15:39

I installed Oracle 12c Data Guard, everything was okey. But, I got an error like below when I wanted to connect data guard database with Toad or SQL Developer. tnsping was okey.

Error

SQL Developer :

Status : Failure -Test failed: IO Error: Got minus one from a read call

Listener.log

10-OCT-2017 15:01:16 * (CONNECT_DATA=(CID=(PROGRAM=SQL Developer)(HOST=__jdbc__)(USER=testuser))(SERVICE_NAME=TDG)(CID=(PROGRAM=SQL Developer)(HOST=__jdbc__)(USER=testuser))) * (ADDRESS=(PROTOCOL=tcp)(HOST=192.168.10.24)(PORT=49834)) * establish * TDG * 12518
TNS-12518: TNS:listener could not hand off client connection
TNS-12547: TNS:lost contact
TNS-12560: TNS:protocol adapter error
TNS-00517: Lost contact
Linux Error: 32: Broken pipe

Solution

If you have grid user to manage listener, you have to give permission on $ORACLE_HOME/bin/oracle executable file. You have to give chmod 6751 permission. This provides that grid user can execute oracle file like oracle user. Oracle open process on OS when you connect to database. If you connect from remote with using listener, listener owner (grid) will want to open new process on OS but grid user cannot open process with using $ORACLE_HOME/bin/oracle file due to do not have permission. So you have to give 6751 permission to use $ORACLE_HOME/bin/oracle file.

[root@tdg bin] chmod 6751 oracle

You can see the same problem at 11g and 12c version of Oracle Data Guard. When oracle rac installation or single instance installation with grid, oracle automatically change permission of $ORACLE_HOME/bin/oracle file to 6751.

290 total views, 25 views today

Tags: Oracle 12c, Oracle Administration, Oracle Error Solutions


Jul 27 2017

Oracle 12c R2 (12.2.0.1) RAC Installation Steps on Oracle Linux 7.3

Category: AdministrationFatih Acar @ 14:37

Oracle Real Application Clusters (Oracle RAC) is a clustered database infrastructure of Oracle Database based on a comprehensive high-availability stack that can be used as the foundation of a database cloud system as well as a shared infrastructure, ensuring high availability, scalability, and agility for any application. Oracle Real Application Cluster has been using with Oracle 9i version since in 2001. This feature provides software for clustering and high availability in Oracle database environments.

Top Benefits of Real Application Clusters (RAC)

  • Ability to spread CPU load across multiple servers
  • Continuous Availability / High Availability (HA)

– Protection from single instance failures

– Protection from single server failures

  • RAC can take advantage of larger SGA sizes than can be accommodated by a single instance commodity server
  • Scalability

 

 

 

Oracle RAC installation steps are a bit long. Firstly, you have to adjust system parameters of operating system on both node and create asm disks. After, you can start to install of grid infrastructure. You can create disk groups for DATA and FRA disk groups after install grid. Finally you can install Oracle RAC database on grid infrastructure and ASM disks. I divide the stages of installation four steps.

First Step : Configure Operation System

Continue reading “Oracle 12c R2 (12.2.0.1) RAC Installation Steps on Oracle Linux 7.3”

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Jun 16 2017

PostgreSQL 10 New Features

Category: AdministrationFatih Acar @ 15:51

PostgreSQL 10 has very good new features. In my opinion, mainly new features are Logical Replication, Improved Parallel Query, Scram Authentication, Declarative Partitioning.

Logical Replication :  PostgreSQL has had physical replication that often called streaming replication since version 9.0, but this requires replicating the entire database, cannot tolerate writes in any form on the standby server, and is useless for replicating across versions or database systems.  PostgreSQL has had logical decoding that basically change capture since version 9.4, which has been embraced with enthusiasm, but it could not be used for replication without an add-on of some sort.  PostgreSQL 10 adds logical replication which is very easy to configure and which works at table granularity, clearly a huge step forward.  It will copy the initial data for you and then keep it up to date after that.

Improved Parallel Query : While PostgreSQL 9.6 offers parallel query, this feature has been significantly improved in PostgreSQL 10, with new features like Parallel Bitmap Heap Scan, Parallel Index Scan, and others.  Speedups of 2-4 x are common with parallel query, and these enhancements should allow those speedups to happen for a wider variety of queries.

SCRAM Authentication :  PostgreSQL offers a remarkable variety of different authentication methods, including methods such as Kerberos, SSPI, and SSL certificate authentication, which are intended to be highly secure.  However, sometimes users just want to use passwords managed by the PostgreSQL server itself.  In existing releases, this can be done either using the passwordauthentication type, which just sends the user-supplied password over the wire, or via the md5authentication type, which sends a hashed and salted version of the password over the wire.  In the latter approach, stealing the hashed password from the database or sniffing it on the wire is equivalent to stealing the password itself, even if you can’t compute a preimage.  PostgreSQL 10 introduces scram authentication, specifically SCRAM-SHA-256, which is much more secure.  Neither the information which the server stores on disk nor the contents of an authentication exchange suffice for the server to impersonate the client.  Of course, the substitution of SHA-256 for MD5 is also a substantial improvement. One point to note is that, unless you are using libpq, you will not be able to use this feature unless your particular client driver has been updated with SCRAM support, so it may be a while before this feature is universally available.

Declarative Partitioning : In previous versions of PostgreSQL, PostgreSQL supported only table inheritance, which could be used to simulate table partitioning, but it was complicated to set up and the performance characteristics were not that great.  In PostgreSQL 10, it’s possible to do list or range partitioning using dedicated syntax, and INSERT performance has been greatly improved.

Also, you can look other new features from here.

 

776 total views, 4 views today


Apr 17 2017

Find And Delete Files Greater Than Given Size on Linux

Category: Linux & UnixFatih Acar @ 19:56

If you want to delete files which are greater than given size on Linux, you can use below examples by changing as your need.

Delete Files

Delete files which are size more than 2 MB. and type is jgp.

[root@testserver ~]# find /tmp/ -type f -size +2M -name “*.jpg” -exec rm -rf {} \;

Delete files which are size more than 2 MB low than 5 MB. and type is jpg.

[root@testserver ~]# find /tmp/ -type f -size +2M -size -5M -name “*.jpg” -exec rm -rf {} \;

Delete files which are size low than 10 MB. and type is zip.

[root@testserver ~]# find /tmp/ -type f -size -10M -name “*.zip” -exec rm -rf {} \;

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Tags: Linux Administration, System Administration


Mar 28 2017

Oracle 11g R2 Resize Redo Log Size on Data Guard and Primary Database

Category: Administration,Backup And Recovery,Errors and SolutionsFatih Acar @ 15:07

Sometimes, you may need to change redo log size to perform optimum size for performance. If you want to change redo log size of both standby side and primary side, you can use below commands.

Current Status Of Redo Logs

Primary Side


SQL> select group#,sum(bytes/1024/1024)"Size in MB" from v$log group by group#;
 
GROUP#     Size in MB
-------    ----------
1          50
2          50
3          50
 
SQL> select group#,sum(bytes/1024/1024)"Size in MB" from v$standby_log group by group#;
 
GROUP#   Size in MB
-------  ----------
 4       50
 5       50
 6       50
 7       50

Standby Side



SQL> select group#, sum(bytes/1024/1024)"Size in MB" from v$loggroup by group#;
 
GROUP# Size in MB
------ -------------
 1     50
 2     50
 3     50
 
SQL> select group#,sum(bytes/1024/1024)"Size in MB" from v$standby_log group by group#;
 
GROUP# Size in MB
------ ----------
 4     50
 5     50
 6     50
 7     50

Change Size Of Redo Logs

Auto File Management Disable on Standby Side


SQL> alter system set standby_file_management=manual

System altered.

Change Redo Log Size Of Primary Side
Continue reading “Oracle 11g R2 Resize Redo Log Size on Data Guard and Primary Database”

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Tags: Database Administration, Oracle Administration


Mar 28 2017

Oracle 11g R2 Open Data Guard Read Write Mode With Flashback Technology And Revert Restore Point

Category: Administration,Backup And RecoveryFatih Acar @ 13:34

You can use flashback technology on standby side. If you want to make application test on database, you can use data guard as read write mode temporarily with flashback technology. You can create a restore point on standby side then you can do any transaction on standby side to test or any other purpose. After you complete your operations on the standby side, you can revert to restore point and again connect to primary side and apply logs from primary side.

This feature can be use for application test operations.

Perform Flashback Steps

Standby Side


SQL> alter database recover managed standby database cancel;

Database altered.

SQL> alter database flashback on;

Database altered.

Note : Check recovery destination and size. You have to have recovery dest and size.

SQL> show parameter recovery

NAME				     TYPE	 VALUE
------------------------------------ ----------- ------------------------------
db_recovery_file_dest		     string	 /oracle/fra
db_recovery_file_dest_size	     big integer 10G
recovery_parallelism		     integer	 0

SQL> create restore point before_test guarantee flashback database;

Restore point created.

Primary Side


SQL> alter system archive log current;

System altered.

Note : Archive dest for standby log sync parameter set defer.

SQL> alter system set log_archive_dest_state_2=defer;

System altered.

Continue reading “Oracle 11g R2 Open Data Guard Read Write Mode With Flashback Technology And Revert Restore Point”

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Tags: Database Administration, Oracle Administration, Oracle Backup and Restore, Oracle Data Guard


Mar 28 2017

Oracle 11g R2 Data Guard Manual Switchover Steps

Category: Administration,Backup And RecoveryFatih Acar @ 09:47

You can use the same steps to switchover for single data guard or multiple data guard configuration.

Switchover operation will convert primary side to data guard and data guard to primary side.

You have to control listeners whether it is running before switchover steps.

Switchover Steps

Primary Side


SQL> alter system archive log current;

SQL> alter database commit to switchover to standby with session shutdown;

SQL> shutdown immediate;

SQL> startup mount;

Data Guard Side
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Tags: Database Administration, Oracle Administration, Oracle Data Guard, Oracle Data Guard Switchover


Mar 27 2017

Oracle 11g R2 Multi Real Time Apply Data Guard Configuration Steps

Category: Administration,Backup And RecoveryFatih Acar @ 16:42

Oracle 11g R2 database supports multi standby database structure up to 30 standby databases. We can use remote destinations for real time apply standby structures with todays network technologies. If your remote destination network is not good, you can use archivelog apply for remote destination with some delay.

System informations are like below.

System Informations

PRIMARY DATABASE
VERSION : 11.2.0.3
IP : 192.168.9.129
SID : PRI
HOSTNAME : primary.localdomain

FIRST STANDBY DATABASE
VERSION : 11.2.0.3
IP : 192.168.9.130
SID : DR1
HOSTNAME : dr1.localdomain

SECOND STANDBY DATABASE
VERSION : 11.2.0.3
IP : 192.168.9.131
SID : DR2
HOSTNAME : dr2.localdomain
Continue reading “Oracle 11g R2 Multi Real Time Apply Data Guard Configuration Steps”

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Tags: Database Administration, Oracle Administration


Mar 21 2017

Oracle 11g R2 Cascade Standby Data Guard Installation and Configuration Steps

Category: Administration,Backup And RecoveryFatih Acar @ 16:32

Oracle 11g R2 database supports cascade standby database structure. If you are using RAC on primary side, your database version has to be least 11.2.0.2 to support cascade standby structure. You can use to reduce the load on your primary database with using cascade standby database structure.

Primary database redo is written to the standby redo log as it is received at a cascading standby database. The redo is not immediately cascaded however. It is cascaded after the standby redo log file that it was written to has been archived locally. A cascaded destination will therefore always have a greater redo transport lag, with respect to the primary database, than the cascading standby database.

Restrictions

  • Cascading Structure is not supported by Data Guard Broker.
  • To use Oracle RAC on primary side, you have to use least 11.2.0.2 verion.
  • Cascaded standby database do not support Real Time Apply

I will configure cascade standby database structure like below schema.

System Informations

PRIMARY DATABASE
VERSION : 11.2.0.3
IP : 192.168.9.129
SID : PRI
HOSTNAME : primary.localdomain

Continue reading “Oracle 11g R2 Cascade Standby Data Guard Installation and Configuration Steps”

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Tags: Database Administration, Oracle Administration


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