How to solve " Oracle Net Services Configuration: Xlib: connection to ":0.0" refused by server Xlib: No protocol specified"

Possible cause of problem:- When you login through "Root"  user and  "SU - oracle"  to switch oracle user then this type of error occurred.

Solution:- To fix this error 

1)  Logout from "Root" user and login through " Oracle" user.

2)  Using "Oracle user run on os promp "NETCA" command to configure listener.

ORA-01102: cannot mount database in EXCLUSIVE mode

When you run startup command then there is a error occured :

ORA-01102: cannot mount database in EXCLUSIVE mode
The possible cause of error are many but I disscuss one of them.

ORA-01102 occurs when you are mounting (opening) a database, typically because another instance is already opened in parallel (exclusive) mode.
SQL> startup;
ORACLE instance started.

Total System Global Area  481259520 bytes
Fixed Size                  1337352 bytes
Variable Size             167774200 bytes
Database Buffers          306184192 bytes
Redo Buffers                5963776 bytes
ORA-01102: cannot mount database in EXCLUSIVE mode
 Solution


SQL> shut abort
ORACLE instance shut down.
SQL> exit      
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

Now kill your process using this command

[oracle@localhost ~]$ ps -ef|grep pmon
oracle    2591 22013  0 21:58 pts/1    00:00:00 grep pmon
oracle    5035     1  0 18:41 ?        00:00:07 asm_pmon_+ASM
oracle   23130     1  0 21:23 ?        00:00:00 ora_pmon_orcl

[oracle@localhost ~]$ kill -9 23130
[oracle@localhost ~]$ kill -9 5035

Now again run...



[oracle@localhost ~]$ sqlplus / as sydba
SQL> startup;


I hope this material help you so much.
If you want to give any suggestion please comment. 

How to overcome error ORA-03113: end-of-file on communication channel during STARTUP

Hello,
This is my firs post .
This post is dedicated to my Anjeet sir. Without help of Anjeet sir I was unable to solve this problem.
First of all I want to say in which senario this error is raised.
Scenario

When I removed control file from default location and create  control file using control file trace command
>alter database backup controlfile to trace as '/home/oracle/contl.sql';

I copy all command in Sql * plus command prompt and create again control file
 When I run Startup  then above error  raised.
The status of trace alert_orcl.log file status is:

Errors in file /u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_lgwr_7154.trc:
ORA-00313: open failed for members of log group 2 of thread 1
Errors in file /u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_lgwr_7154.trc:
ORA-00313: open failed for members of log group 2 of thread 1
Mon Apr 13 09:39:24 2015
ARC1 started with pid=21, OS id=7203 
Mon Apr 13 09:39:24 2015
ARC2 started with pid=22, OS id=7209 
Errors in file /u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_ora_7199.trc:
ORA-00313: open failed for members of log group 1 of thread 
ORA-00312: online log 2 thread 1: '/u01/app/oracle/oradata/orcl/redo02.log'
ORA-00312: online log 2 thread 1: '/home/oracle/disk02/redo05.log'

USER (ospid: 7199): terminating the instance due to error 313
Solution

>startup mount;

>recover database untill cancel;

>alter database open resetlogs;