Archive for

ASM ab_+ASM.dat hc_+ASM.dat

ab_+ASM.dat : This file generated when asm instance startup. this file  is used by the RDBMS instance to determine the appropriate enviornment information whenever the RDBMS instance connects to the asm instance. If this file is removed, RDBMS instance can not able to connect to ASM

For Example :

[oracle@asmoracle ~]$ cd /u01/app/oracle/11.2.0/grid/dbhome_1/dbs/
[oracle@asmoracle dbs]$ ls
ab_+ASM.dat hc_+ASM.dat initasm.ora init.ora orapw+ASM spfile+ASM.ora

Removed this file or rename this file and then try to startup the RDBMS instance

[oracle@asmoracle dbs]$ mv ab_+ASM.dat ab_+ASM.dat_new

SQL> startup
ORA-01078: failure in processing system parameters
ORA-01565: error in identifying file ‘+DATA/asmoracle/spfileasmoracle.ora’
ORA-17503: ksfdopn:2 Failed to open file +DATA/asmoracle/spfileasmoracle.ora
ORA-27300: OS system dependent operation:open failed with status: 2
ORA-27301: OS failure message: No such file or directory
ORA-27302: failure occurred at: sskgmsmr_7

So I can not able to start the database instance.

After I revert back these file, I can able to connect.

[oracle@asmoracle dbs]$ mv ab_+ASM.dat_new ab_+ASM.dat

SQL> startup
ORACLE instance started.

Total System Global Area 839282688 bytes
Fixed Size 2217992 bytes
Variable Size 524290040 bytes
Database Buffers 310378496 bytes
Redo Buffers 2396160 bytes
Database mounted.
Database opened.

Note that the authentication for the connection is not based on the information in the *.dat file.

But I renamed that file and done some transaction and also I try to create tablespace,  it showing end of file communication error. Again i revert back these file and started the database and again i renamed that file and done some transaction and also created tablespace, now its okay even these file not available. then Why this below error occured before? I want to know more detail, I will share this details once my investigate done.

[oracle@asmoracle dbs]$ mv ab_+ASM.dat  ab_+ASM.dat_new

SQL> conn test/test
Connected.
SQL> create table test(empno number,city varchar2(20));

Table created.

SQL> insert into test values(001, ‘dubai’);

1 row created.

SQL> commit;

Commit complete.

SQL> insert into test values(002, ‘trichy’);

1 row created.

SQL> commit;

Commit complete.

SQL> select count(*) from tab;

COUNT(*)
———-
1

SQL> select * from test;

EMPNO CITY
———- ——————–
1 dubai
2 trichy

 

SQL> conn / as sysdba
Connected.
SQL> create tablespace testtbs datafile ‘+DATA’ size 1m;
create tablespace testtbs datafile ‘+DATA’ size 1m
*
ERROR at line 1:
ORA-03113: end-of-file on communication channel
Process ID: 4644
Session ID: 1 Serial number: 17

 

Again I revert back these file and started the database and then renamed that file but now i done many activities nothing happen. So want to investigate this details

[oracle@asmoracle dbs]$ mv ab_+ASM.dat_new ab_+ASM.dat

SQL> startup
ORACLE instance started.

Total System Global Area 839282688 bytes
Fixed Size 2217992 bytes
Variable Size 524290040 bytes
Database Buffers 310378496 bytes
Redo Buffers 2396160 bytes
Database mounted.
Database opened.

[oracle@asmoracle dbs]$ mv ab_+ASM.dat  ab_+ASM.dat_new

SQL> create tablespace testtbs datafile ‘+DATA’ size 1m;

Tablespace created.

 

hc_+ASM.dat :

EM uses this file for instance health-check monitoring. If this file is removed, the health check information for the instance

will be inaccurate.

Note : Don’t remove these files

ASM Startup

The startup for ASM instance are similar to those for RDBMS instances

For Example Nomount option start  up an asm instance without mounting any diskgroups.

SQL> startup nomount
ASM instance started

Total System Global Area 283930624 bytes
Fixed Size 2212656 bytes
Variable Size 256552144 bytes
ASM Cache 25165824 bytes

SQL> select name,state from v$asm_diskgroup;

NAME STATE
—————————— ———–
DATA DISMOUNTED

Mount option is used to mount the all diskgroup specified in ASM_DISKGROUPS init.ora parameter.

SQL> ALTER DISKGROUP ALL MOUNT;

Diskgroup altered.

SQL> select name,state from v$asm_diskgroup;

NAME STATE
—————————— ———–
DATA MOUNTED

 

If no diskgroup listed in the init.ora file, then the message “ORA-15110: no diskgroups mounted” is displayed. If the listed diskgroups cannot be mounted, then the following messages appear: “ORA-15032: not all alterations performed,” and, “ORA-5063: ASM discovered an insufficient number of disks for diskgroup <diskgroup name>.”

In Oracle Database 11g, ASM introduced the RESTRICTED startup option for the MOUNT command. When an ASM instance is started with the RESTRICTED option, the starting ASM instance exclusively mounts all of the diskgroups listed in  the ASM_DISKGROUPS parameter, and no RDBMS access is permitted in this mode.When the RESTRICTED startup option is used on a diskgroup in an ASM clustered(RAC) environment, no other ASM instance in the cluster can access that diskgroup.The RESTRICTED option is particularly useful when performing maintenance, such as a rebalance, on a diskgroup or set of diskgroups.

For Example :

SQL> startup restrict

ASM instance started

Total System Global Area 283930624 bytes
Fixed Size 2212656 bytes
Variable Size 256552144 bytes
ASM Cache 25165824 bytes
ASM diskgroups mounted

SQL> SELECT NAME, STATE FROM V$ASM_DISKGROUP;

NAME STATE
—————————— ———–
DATA RESTRICTED

I am trying to start the database but getting error

SQL> startup
ORA-01078: failure in processing system parameters
ORA-01565: error in identifying file ‘+DATA/asmoracle/spfileasmoracle.ora’
ORA-17503: ksfdopn:2 Failed to open file +DATA/asmoracle/spfileasmoracle.ora
ORA-15056: additional error message
ORA-17503: ksfdopn:DGOpenFile05 Failed to open file +DATA/asmoracle/spfileasmoracle.ora
ORA-17503: ksfdopn:2 Failed to open file +DATA/asmoracle/spfileasmoracle.ora
ORA-15236: diskgroup DATA mounted in restricted mode
ORA-06512: at line 4
SQL>

After maintenance work, you need to shutdown the asm instance and startup the asm

SQL> shutdown immediate
ASM diskgroups dismounted
ASM instance shutdown

SQL> startup
ASM instance started

Total System Global Area 283930624 bytes
Fixed Size 2212656 bytes
Variable Size 256552144 bytes
ASM Cache 25165824 bytes
ASM diskgroups mounted

SQL> SELECT NAME, STATE FROM V$ASM_DISKGROUP;

NAME STATE
—————————— ———–
DATA MOUNTED