Add a new disk to asm diskgroup

1.PURPOSE AND SCOPE

In this article i am going to explation how to add new disk to the diskgroup which used by database.Before starting i wanted to give some informations about our steps. In this practice we had got a disk named DISK4 and this isnt belong to single diskgroup.First of all i am going to check the stability of DISK4, if disk success i am going to create a different diskgroup and try to add it there.If this step also succeed we are going to add this disk to diskgroup which used by production diskgroup.

2.PRACTICE

2.1. Time to control stability of  DISK4 . (If you have got RAC env, you need to do this every single node)

[root@oracle ~]# /etc/init.d/oracleasm  scandisks

Scanning the system for Oracle ASMLib disks:               [  OK  ]

[root@oracle ~]# /etc/init.d/oracleasm  listdisks

DISK1

DISK2

DISK3

DISK4

[root@oracle ~]# /etc/init.d/oracleasm  querydisk DISK4

Disk "DISK4" is a valid ASM disk

[root@oracle ~]# ls -l /dev/oracleasm/disks/DISK4

brw-rw---- 1 oracle dba 8, 34 Jun 23 23:40 /dev/oracleasm/disks/DISK4

2.2.   Now we are going to check asm headers. For this step we need to use ASM metadata editor kfed. If everything is okey about asm header we need to see “kfbh.type: 1 ; 0x002: KFBTYP_DISKHEAD”

[root@oracle ~]# kfed read /dev/oracleasm/disks/DISK4
 kfbh.endian: 1 ; 0x000: 0x01
 kfbh.hard: 130 ; 0x001: 0x82
 kfbh.type: 1 ; 0x002: KFBTYP_DISKHEAD
 ...
 kfbh.check: 1539641569 ; 0x00c: 0x5bc510e1
 ...
 kfdhdb.driver.provstr: ORCLDISKDISK4 ; 0x000: length=13
 ...
 kfdhdb.dsknum: 0 ; 0x024: 0x0000
 kfdhdb.grptyp: 2 ; 0x026: KFDGTP_NORMAL
 kfdhdb.hdrsts: 3 ; 0x027: KFDHDR_MEMBER
 kfdhdb.dskname: PLAY0 ; 0x028: length=5
 kfdhdb.grpname: PLAY ; 0x048: length=4
 kfdhdb.fgname: P1 ; 0x068: length=2
 ...
 kfdhdb.blksize: 4096 ; 0x0ba: 0x1000
 kfdhdb.ausize: 4194304 ; 0x0bc: 0x00400000
 ...
 kfdhdb.dsksize: 1221 ; 0x0c4: 0x000004c5
 ...

2.3.1. Lets connect to ASM instance.

[oracle@oracle ~]$ export ORACLE_SID=+ASM

[oracle@oracle ~]$ sqlplus /  as sysdba

SQL*Plus: Release 11.1.0.6.0 - Production on Fri Jun 24 00:11:02 2011

Copyright (c) 1982, 2007, Oracle.  All rights reserved.

Connected to:

Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production

With the Partitioning, OLAP, Data Mining and Real Application Testing options

2.3.2. Lets create a new diskgroup and add DISK4 to this group.

P.S.: While crating diskgroup it gave error about asm_diskstring because of it i am adding information about this too maybe it would be usefull for you.

SQL> CREATE DISKGROUP TEST EXTERNAL REDUNDANCY DISK '/dev/oracleasm/disks/DISK4';

CREATE DISKGROUP TEST EXTERNAL REDUNDANCY DISK '/dev/oracleasm/disks/DISK4'

*

ERROR at line 1:

ORA-15018: diskgroup cannot be created

ORA-15031: disk specification '/dev/oracleasm/disks/DISK4' matches no disks

ORA-15014: path '/dev/oracleasm/disks/DISK4' is not in the discovery set

SQL> show parameter disk

NAME                                 TYPE        VALUE

------------------------------------ ----------- ------------------------------

asm_diskgroups                       string      DATA1, DATA2

asm_diskstring                       string

disk_asynch_io                       boolean     TRUE

SQL> alter system set asm_diskstring='/dev/oracleasm/disks/DISK*';

alter system set asm_diskstring='/dev/oracleasm/disks/DISK*'

*

ERROR at line 1:

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

ORA-15014: path 'ORCL:DISK1' is not in the discovery s

SQL> alter system set asm_diskstring='ORCL:DISK*';

System altered.

SQL> CREATE DISKGROUP TEST EXTERNAL REDUNDANCY DISK 'ORCL:DISK4';

Diskgroup created.

2.4. We created TEST diskgroup so lets execute query to is it mounted and work correctly.

SQL> SELECT STATE, NAME FROM V$ASM_DISKGROUP;

STATE       NAME
----------- ------------------------------
MOUNTED     DATA1
MOUNTED     DATA2
MOUNTED     TEST

2.5. Seems like DISK4 passed our exams so lets drop TEST diskgroup

SQL> drop diskgroup test;

Diskgroup dropped.

2.6. Before adding disk to diskgroup lets check size of current diskgroups.

SQL> COL % FORMAT 99.0
SQL> SELECT name, free_mb, total_mb, free_mb/total_mb*100 "%" FROM v$asm_diskgroup;
NAME                              FREE_MB   TOTAL_MB     %
------------------------------ ---------- ---------- -----
DATA1                                8554      10196  83.9
DATA2                                4902       5137  95.4

2.7. Time to add DISK4 to DATA1 diskgroup.

SQL>  ALTER DISKGROUP DATA1 ADD DISK 'ORCL:DISK4';

Diskgroup altered.

2.8. Lets check diskgroup sizes again.

 
SQL> SELECT name, free_mb, total_mb, free_mb/total_mb*100 "%" FROM v$asm_diskgroup;

NAME                              FREE_MB   TOTAL_MB     %
------------------------------ ---------- ---------- -----
DATA1                               13689      15333  89.3
DATA2                                4902       5137  95.4