Oracle's 10gR2 ASM with Standard Linux I/O in CentOS 4.1 environment
This method creates Oracle database files on raw character devices
managed by ASM using standard Linux I/O system calls.It requires to create RAW devices for all disk partitions used by ASM.
1.Install CentOS 4.1
2.Run as root:
# groupadd dba # group of users to be granted SYSDBA system privilege
# groupadd oinstall # group owner of Oracle files
# useradd -c "Oracle software owner" -g oinstall -G dba oracle
# passwd oracle
# mkdir -p /u01/app/oracle
# chown -R oracle.oinstall /u01
# mkdir -p /u02/oradata/data
# chown -R oracle.oinstall /u02
Just as an example create 4 partitions:
/dev/hda6,/dev/hdc6 5 GB each one
/dev/hda7,/dev/hdc7 3 GB each one
Create raw devices modifying file /etc/sysconfig/rawdevices as follows:
Put in /etc/rc.d/rc.local
chown oracle:dba /dev/raw/raw*
chmod 660 /dev/raw/raw*
I was experiencing problems with loosing "oracle:dba" permissions after Linux reboot. It came up with "root:disk" .
Run as root:-
# /sbin/service rawdevices restart
Tune /etc/sysctl.conf,/etc/security/limits.conf,/etc/pam.d/login, /etc/profile.
and oracle's shell environment as advised in .
Login as oracle:-
$ cd /tmp/database
Select " Advanced installation" and
create ASM instance with $ORACLE_HOME=/u01/app/oracle/oracle/product/10.2.0/db_1
During this run create disk group RAWDATA1 with normal redundancy mirroring /dev/raw/raw1 and /dev/raw/raw2
You should be fine with discovering raw devices if permissions are in place (oracle:dba)
Export ORACLE_HOME for ASM instance and corresponding PATH.
Then run "dbca" to create disk group RAWDATA2 with
normal redundancy mirroring /dev/raw/raw3 and /dev/raw/raw4
Select " Advanced installation" and create new ASM-database placed RAWDATA1 diskgroup
with $ORACLE_HOME=/u01/app/oracle/oracle/product/10.2.0/db_2 .
Modify ~oracle/.bash_profile correspondently.Relogin as oracle.
$ sqlplus /nolog
SQL> conn / as sysdba
SQL> shutdown immediate;
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 285212672 bytes
Fixed Size 1218968 bytes
Variable Size 88082024 bytes
Database Buffers 188743680 bytes
Redo Buffers 7168000 bytes
SQL> alter database archivelog;
SQL> alter database rawdbs flashback on;
SQL> alter database open;
Open Enterpise Manager console.(Enterprise Manager 10g Database Control URL http://ServerCentOS41:1158/em). Put flashback recovery area in RAWDATA2 modifying corresponding value on Recovery Settings page of EM.
Last edited by dbaxps; 11-19-2005 at 07:54 AM.
Using Block Devices for Oracle 10g Release 2 in RHEL 4
Per Werner Puschitz:-
For Oracle 10g Release 2 in RHEL 4 it is not recommended to use raw devices but to use block devices instead. Raw I/O is still available in RHEL 4 but it is now a deprecated interface. In fact, raw I/O has been deprecated by the Linux community. It has been replaced by the O_DIRECT flag which can be used for opening block devices to bypass the OS cache. Unfortunately, Oracle Clusterware R2 OUI still requires raw devices or a Cluster File System.
By default, reading and writing to block devices are buffered I/Os. Oracle 10g R2 now automatically opens all block devices such as SCSI disks using the O_DIRECT flag, thus bypassing the OS cache. For example, when you create disk groups for ASM and you want to use the SCSI block devices /dev/sdb and /dev/sdc, you can simply set the Disk Discovery Path to "/dev/sdb, /dev/sdc" to create the ASM disk group. There is no need to create raw devices and to point the Disk Discovery Path to it.
Last edited by dbaxps; 07-03-2006 at 07:56 AM.
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