Oracle 12c DBA Training

DBA University is excited to announce Oracle DBA Training course in the latest Oracle 12c R1 and 12c R2 versions Each training schedule runs for a period of 64 hours spread over 8 weekends. The live online training sessions are held from 8:00 am to 12:30 pm central time (with a 30 minute break) every Saturday and Sunday. We also have an on demand training (recorded training) offering for this course.

This course will help students prepare for majority of the topics required to pass the Oracle Database 12c Administration 1Z0-062 examination towards Oracle OCA certification (Oracle Certified Associate). It contains various other topics with practical exercises that are required for real world success.

Course Highlights

1) 64 hours course duration.

2) Training will be on the latest Oracle 12c R2 and 12c R1 versions.

3) Saturday, Sunday - 8:00 am to 12:30 pm central time (with a 30 minute break).

4) 500+ pages training material available for email download through Dropbox link.

Lab work

1) Each student will get a remote lab computer to practice the course work.  

2) The training will be on both Oracle 12c R2 and 12c R1 versions with Linux 7 64-bit as the operating system.

3) 16 hours Remote LAB access on Saturday, Sunday

4) 6 hours Remote LAB access on weekday evenings.

5) Students can use the Windows Remote Desktop Connection program to connect to the remote lab server.

Links and Resources

1) Download Oracle DBA Training course brochure

2) Click here for a FREE DEMO session  (Name and Email only)

3) Click here to register for the live online training course
4) Students who are interested in the on demand training (recorded training) should click here to purchase.

How to configure and start vncserver on Linux 7

Introduction

The procedure to enable vncserver and startup automatically upon server reboot has been changed in Red Hat compatible linux operating systems such as Red Hat Linux 7.x, Oracle Enterprise Linux 7.x and CentOS etc. If your operating system has version 6.x, then please follow this article instead.

Details

1) Login as root operating system user.

2) rm -rf  /tmp/.X11-unix/

3) cd  /lib/systemd/system

4) Make a copy of vncserver@.service

5) Edit vncserver@.service and replace <USER>  with the actual operating system user name that owns the vnc service. Leave the remaining lines of the file unmodified.

6) systemctl  daemon-reload

7) systemctl  enable  vncserver@:1.service

8) systemctl  start  vncserver@:1.service

9) Edit /etc/rc.d/rc.local and add the line service iptables restart

10) chmod  +x  /etc/rc.d/rc.local

11) Optionally, sudo su - <USER>  and then execute the vncpasswd command to change the vncserver password.
12) Reboot the server.

If the vncserver program is still not getting started automatically, then add the below lines directly in the /etc/rc.d/rc.local file.

rm -rf  /tmp/.X11-unix/
systemctl  daemon-reload
systemctl  enable  vncserver@:1.service
systemctl  start  vncserver@:1.service
service iptables restart

Verification

1) Launch TigerVNC Viewer

2) IP address:5901 

It should prompt for Password and then it should connect successfully

How to install X Windows on Linux

The following packages (a.k.a RPMs) are required to setup X Windows on Linux, specifically Oracle Enterprise Linux (OEL) with the UEK kernel. It is tested successfully on Oracle Linux 7 update 3 for x86_64. These packages also install KDE as the default desktop environment on this Linux operating system.

Login as root and run the yum install package command for each such package below.

yum install vnc
yum install vnc-server 
yum install xterm
yum groupinstall "X Window System"  
yum install kdebase
yum install gnome-terminal
yum groupinstall "KDE"

TNS-01189: The listener could not authenticate the user

In older versions of Oracle database such as Oracle 9i etc, one can stop a listener remotely. This was a serious security problem because all that is needed by any client or end user is the listener name and a TNS entry(listener port and host name) to shutdown the listener sitting from that client machine !!!. This can be prevented by securing the listener with a password. We published a blog post about this security issue a few years ago.

But this password feature is deprecated since Oracle database 11g R2 release. This is no security problem because the listener is now secured using local operating system authentication. Therefore, no client or end user can remotely shutdown a database listener anymore.  If one attempts to stop a database listener process from a remote machine, one receives the error "TNS-01189: The listener could not authenticate the user".  A listener can be only be stopped after logging into the database server (and connecting to the Oracle software owner account) that hosts the listener process. This experience is similar to how Oracle does not allow remote connections to the sys built-in administrative database account.

Therefore, there is no need of protecting Oracle database listeners with passwords since Oracle database 11g R2 release.

Microsoft SQL Server 2016 DBA Training

DBA University is excited to announce MS SQL Server 2016 DBA Training online course. Each training schedule runs for a period of 40 hours spread over 7 weeks. The training sessions are held from 7:30 pm to 9:30 central time Monday, Tuesday and Sunday each week.

Course Highlights

1) 40 hours course duration.

2) Training will be on the latest Microsoft SQL Server 2016 version.

3) Monday, Tuesday, Sunday - 7:30 pm Central Time to 9:30 pm Central Time online.

4) Training materials available for download through Dropbox link.

5) Click here for a FREE DEMO session  (Name and Email only)

6) Click here to register for the online training course

Lab work

1) Each student will get a remote lab computer to practice the course work.  

2) The training will be on Microsoft SQL Server 2016 version with Windows Server 2012 R2 as the operating system.

3) 10 hours Remote LAB access on Saturday, Sunday

4) 6 hours Remote LAB access on weekday evenings.

5) Students can use the Windows Remote Desktop Connection program to connect to the remote lab server.

Links and Resources

1) Download MS SQL Server 2016 DBA course brochure

2) Click here for a FREE DEMO session  (Name and Email only)

3) Click here to register for the online training course

How to restart Oracle dbca after a failed database creation with ASM

Introduction

This article provides you the details how to clean up the files created by dbca tool as part of a partially created Oracle database using Oracle Automatic Storage Management (Oracle ASM). Let us assume the ASM instance name is +ASM, the ASM diskgroup name is +DATA, the Oracle database name that failed to be created successfully as SALESDB with 12c R1 version.

This article also provides the steps to remove all references that still exist for the SALESDB database before a retry.

Solution

1) .  oraenv  (Note the space after the DOT symbol. Set +ASM environment)

2) echo  $ORACLE_SID  (Must show +ASM)

3) sqlplus /  as  sysasm

4) select  name from  v$asm_alias;

Let us find the control file alias name of the failed SALESDB database. It starts with Current. For example, it may be Current.257.912291913. Therefore the full path of the control file in ASM diskgroup is +DATA/SALESDB/CONTROLFILE/Current.257.912291913

5) exit

6) . oraenv (Note the space after the DOT symbol. Set SALESDB environment.)

7) echo  $ORACLE_SID  (Must show SALESDB.)

8) cd  $ORACLE_HOME/dbs

9) Remove any existing initSALESDB.ora or spfileSALESDB.ora that was created during the initial execution of dbca.

10) vi initSALESDB.ora  (Add the below initialization parameters.)

db_name=SALESDB

control_files=+DATA/SALESDB/CONTROLFILE/Current.257.912291913

compatible=12.1.0

11) sqlplus / as sysdba

12) startup mount force restrict;

13) exit

14) rman

15) connect /

16) drop database;

17) exit

18) Delete the initSALESDB.ora

19) Remove the SALESDB entry in /etc/oratab file.

20) cd $ORACLE_BASE/fast_recovery_area

21) rm -rf SALESDB (Delete any files created by dbca in the Fast Recovery Area.)

22) cd $ORACLE_BASE/admin

23) rm -rf SALESDB

24) cd $ORACLE_BASE/diag/rdbms

25) rm -rf salesdb (Delete the diagnostic files directory structure for SALESDB.)

26) cd $ORACLE_BASE/cfgtoollogs/dbca

27) rm -rf SALESDB

Conclusion

Once the above steps are completed, the +DATA diskgroup should not have any more ASM files for the SALESDB database. Also, all SALESDB references on the database server will be removed. Finally, start the dbca tool again and this time, hopefully, your SALESDB database creation will be successful.

oracle training on demand

We are pleased to announce that DBA University is now offering all Oracle training courses on demand.

Highlights

1) Each student gets 3 months of on demand access to a recently concluded live training course through our high quality cloud based videos. 

2) Students also get all the training materials through Dropbox downloads.

3) Two months of dedicated access to our cloud based remote lab servers.

Registration  Please click here for registration.

Oracle on demand training courses

1) Oracle DBA

2) Oracle SQL Training

3) Oracle PL/SQL Training

4) Oracle RAC, ASM, DG Training