SETUP ASM&ASMLib on Multipath Disks

1.       Install Correct Packages

We must be careful while downloading correct rpms. Before download the rpms, check your kernel version and processor(32 bit or 64 bit):

oracleasm-(kernel)  ---  must be same version with the kernel

oracleasmlib          --- can be the latest version of correct 32 or 64 bit version

oracleasm-support --- can be the latest version of correct 32 or 64 bit version

[root@racnode1 ~]# uname -a

Linux racnode1.msb.bak 2.6.18-194.el5 #1 SMP Tue Mar 16 21:52:39 EDT 2010 x86_64 x86_64 x86_64 GNU/Linux

[root@racnode1 ~]# rpm -qa | grep asm

oracleasm-support-2.1.8-1.el5

oracleasmlib-2.0.4-1.el5

oracleasm-2.6.18-194.el5-2.0.5-1.el5

[root@racnode1 ~]#

if you downloaded and installed wrong “oracleasm-(kernel)” rpm, you can get the following errors:

[root@racnode1 bin]# /etc/init.d/oracleasm start

Initializing the Oracle ASMLib driver: [FAILED]

[root@racnode1 bin]# more /var/log/oracleasm

"/var/log/oracleasm"

"/var/log/oracleasm" 145L, 5999CCreating /dev/oracleasm mount point: /dev/oracleasm

Loading module "oracleasm": failed

Unable to load module "oracleasm"

Creating /dev/oracleasm mount point: /dev/oracleasm

Loading module "oracleasm": failed

Unable to load module "oracleasm"

Reloading disk partitions: done

Cleaning any stale ASM disks...

Scanning system for ASM disks...

oracleasm-read-label: Unable to open device "/dev/sdb1": No such file or directory

oracleasm-read-label: Unable to open device "/dev/dm-0": No such file or directory

oracleasm-read-label: Unable to open device "/dev/dm-0": No such file or directory

oracleasm-read-label: Unable to open device "/dev/dm-0": No such file or directory

oracleasm-read-label: Unable to open device "/dev/dm-0": No such file or directory

oracleasm-read-label: Unable to open device "/dev/dm-1": No such file or directory

oracleasm-read-label: Unable to open device "/dev/dm-1": No such file or directory

oracleasm-read-label: Unable to open device "/dev/dm-1": No such file or directory

oracleasm-read-label: Unable to open device "/dev/dm-1": No such file or directory

2.       Check your disks

[oracle@racnode1 ~]$ ls -lrt /dev/mapper/

total 0

brw-rw---- 1 root disk 253,  8 May 15 12:47 oradata2p1

brw-rw---- 1 root disk 253,  9 May 15 12:47 oradata3p1

brw-rw---- 1 root disk 253, 10 May 15 12:47 oradata1p1

3.       Create ASM disks

[root@racnode1 ~]# /etc/init.d/oracleasm createdisk ASM1 /dev/mapper/oradata1p1

[root@racnode1 ~]# /etc/init.d/oracleasm createdisk ASM2 /dev/mapper/oradata2p1

4.       For RAC systems, run the command for every node

[root@racnode1 ~]# /etc/init.d/oracleasm scandisks

Scanning the system for Oracle ASMLib disks:               [  OK  ]

[root@racnode1 ~]# /etc/init.d/oracleasm listdisks

ASM1

5.       Configure ASMLib for multipath (do the following operations for every node)

Modify /etc/sysconfig/oracleasm

ORACLEASM_SCANORDER=”dm”

ORACLEASM_SCANEXCLUDE=”sd”

Restart asmlib

/etc/init.d/oracleasm stop

/etc/init.d/oracleasm start

6.       Check disk configuration

ASMLib checks the /proc/partitions to detect the disks:

[root@racnode1 ~]# cat /proc/partitions | grep dm-

 253     0   90963968 dm-0

 253     1   51478528 dm-1

 253     2  536870912 dm-2

 253     3  536870912 dm-3

 253     4  536870912 dm-4

 253     5  536870912 dm-5

 253     6  104857600 dm-6

 253     7  536868171 dm-7

 253     8  536868171 dm-8

 253     9  536868171 dm-9

 253    10  536868171 dm-10

 253    11  104856223 dm-11

7.       ASM disks are mounted under the /dev/oracleasm/disks

root@racnode1 ~]# ls -la /dev/oracleasm/disks

brw-rw---- 1 oracle oinstall 253, 10 May 15 12:48 ASM1

brw-rw---- 1 oracle oinstall 253,  8 May 15 12:48 ASM2

8.       Major and Minor numbers of the disks have to be same in both /proc/partitions/ and /dev/oracleasm/disks/

/proc/partitions         253    10  536868171 dm-10

brw-rw---- 1 oracle oinstall 253, 10 May 15 12:48 ASM1

[root@racnode1 ~]# /etc/init.d/oracleasm querydisk -d ASM1

Disk "ASM1" is a valid ASM disk on device /dev/dm-10[253,10]

How to change tablespace of sys.aud$ and how to shrink it?

To shrink the aud$ table, you have to enable "row movement". The default tablespace of aud$ is SYSAUX and because of that you need to change its tablespace first.

With 11g, changing the tablespace of aud$ table is supported.

begin

dbms_audit_mgmt.set_audit_trail_location(
audit_trail_type => dbms_audit_mgmt.audit_trail_aud_std,          audit_trail_location_value => 'AUDTBS');

end;

alter table sys.aud$ enable row movement;

alter table sys.aud$ shrink space cascade;

How to reset an expired database user without changing the password?

The simple method to reset a user is changing the password. If you dont have chance to change the password and if you can not remember the old one, you can use the following method:

select dbms_metadata.get_ddl('USER', username), '''[^'']+''') pswd, username from dba_users;



You can find the hashed passwords for all users in the database with this query. 

After that you can set the old password and reset the account.


alter user HR identified by values 'S:ASSDSKDEIRUIERUTEUYTEIEORIEORIEPORI;ERIUERIUTY';

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