Error connecting ASM ORA-15055: unable to connect to ASM instance Fatal NI connect error 12547 ORA-12547: TNS:lost contact

TNS-12547: TNS:lost contact
    ns secondary err code: 12560
    nt main err code: 517
ORA-15055: unable to connect to ASM instance
ORA-12547: TNS:lost contact
TNS-12545: Connect failed because target host or object does not exist


Cause:

$GRID_HOME/bin/oracle or $ORACLE_HOME/bin/oracle permission has been changed

ls -al $GRID_HOME/bin/oracle
-rwxr-x--x 1 grid oinstall 200678464 Jun 28 14:54 oracle 

ls -al $ORACLE_HOME/bin/oracle
-rwxr-x--x 1 oracle asmadmin 228886191 Jun 28 15:41 oracle

Solution:

Change permissions as below 

cd $GRID_HOME/bin
chmod 6751 oracle

cd $ORACLE_HOME/bin
chmod 6751 oracle

Once it looks as below the problem is solved...

ls -l $GRID_HOME/bin/oracle
-rwsr-s--x 1 grid oinstall 203974257 Jun 29 09:30 oracle

ls -l $ORACLE_HOME/bin/oracle
-rwsr-s--x 1 oracle oinstall 232399431 Jun 29 13:47 oracle

ORA-02097: parameter cannot be modified because specified value is invalid

Alert log Entry

ORA-02097: parameter cannot be modified because specified value is invalid
ORA-00068: invalid value 4000 for parameter parallel_max_servers, must be between 0 and 3600
CKPT (ospid: 3277292): terminating the instance due to error 2097
Mon Jun 15 12:30:13 

Cause 1
It might be caused by the current system level change on the number of CPU which will shut down all the instances on the same server.

Solution

Just start the instances no need to worry oracle will take care of itself.

Cause 2

Related to parallel_max_servers wich is calculated 

PARALLEL_THREADS_PER_CPU * CPU_COUNT * concurrent_parallel_users * 5

and its value should range between 0 and 300.

Solution

Modify its value reasonably using alter system.

Sysman password changing in oracle 11g

We may need to change the passwords of different users including sysman as a security measure or for other reason.But after changing the sysman password the enterprise manager console may not work, because we need to update the password using the following setps

step 1. Stop the dbconsole

export ORACLE_UNQNAME=DBNAME
emctl stop dbconsole

step 2. connect as sysdba and change the passowrd of sysman as required

SQL> alter user sysman idntified by XXXXX;

step 3. Update the password

emctl setpasswd dbconlole

step 4. Start the dbconsole

export ORACLE_UNQNAME=DBNAME
emctl start dbconsole


Now the enterprise manager works properly