Oracle 10g Database on Raw Device

Creating Oracle database that uses Raw Device option for Storing database files (For RHEL 4 / 3 / 2.1/ CentOS 4 / 3 / 2)
By Bhavin Hingu

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Raw Devices are disk partitions or logical volumes that have not been formatted with file system. When you use raw devices for database file storage, Oracle writes data directly to the partition or volume, bypassing the operating system file layer. For this reason, you can sometimes achieve performance gains by using raw devices. However, because raw devices can be difficult to create and administer, and because the performance gains over the modern are minimal, Oracle recommends that you choose Automatic Storage Management (ASM) or file system storage in preference to raw devices.

Tasks covered:

Partitioning Disk:

Creating Volumes and the Volume Group:

Creating Physical Volume
Creating Volume Group
Creating logical volumes

Binding Volumes to Raw devices

Creating dbca raw device mapping file

Creating required Directories
Adding entries to the config file

Linking Raw device to the physical filename

Updating .bash_profile file. for oracle.
Creatying database manuall\y without dbca:

Partitioning Disk (s):

Please goto "creating paritions" to create the partitions. It is preferable to use single-whole disk partition (e.g /dev/sda)
instead of multi-partitioned disk (e.g, /dev/sda3)

Creating Volume Group oracle_vg and Logical Volumes under this group:

Creating Physical Volume (/dev/sda3):

The partition table looks like below. I have used /dev/sda3 partition where Logival Volumes will be created using LVM
(Logical Volume Manager).

[root@shree root]# fdisk -l

Disk /dev/sda: 122.9 GB, 122942324736 bytes
255 heads, 63 sectors/track, 14946 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot    Start       End    Blocks   Id System
/dev/sda1             1      3648 29302528+ 83 Linux
/dev/sda3          4866      7905 24418800   83 Linux
/dev/sda4          7906     14946 56556832+ 83 Linux

Disk /dev/hda: 60.0 GB, 60022480896 bytes
255 heads, 63 sectors/track, 7297 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot    Start       End    Blocks   Id System
/dev/hda1   *         1      1567 12586896   83 Linux
/dev/hda2          1568      1632    522112+ 83 Linux
/dev/hda3          1633      2154   4192965   82 Linux swap
/dev/hda4          2155      7297 41311147+   5 Extended
/dev/hda5          2155      7297 41311116   83 Linux

Disk /dev/hdb: 122.9 GB, 122942324736 bytes
255 heads, 63 sectors/track, 14946 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot    Start       End    Blocks   Id System
/dev/hdb1   *         1      1217   9775521   83 Linux
/dev/hdb2          1218      6081 39070080   83 Linux
/dev/hdb3          6082     10945 39070080   83 Linux
/dev/hdb4         10946     14946 32138032+ 83 Linux
[root@shree root]#

we need to stamp the raw disk or partition (In our example /dev/sda3) to be recognised as Volume Group disk.
We execute the pvcreate command as root to stamp the disk.

[root@shree ~]# pvcreate -d /dev/sda3

Creating Volume Group:

Then we need to create a volume group oracle_vg on top of the stamped disk (/dev/sda3). The below comamd will allow
128 logical and 128 physical partitions with the extent size of 512 KB.

[root@shree ~]# vgcreate -l 128 -p 128 -s 512k oracle_vg /dev/sda3

Creating Logcal Volumes:

Under this Volume Group (oracle_vg), we will create logical volumes one for each tablespaces, redolog files and control files.
The naming convention for the logical volumes should be dbname_objectname_raw_sizem. In our example the dbname is test and so
the logical volume name for the tablespace (object) SYSTEM of size 500M is test_system_raw_500m. Oracle recommends to create
the following number of logical volumes of mentioned size for each objects.

Number	Partition Size (MB)	Purpose
1	500	SYSTEM tablespace
1	500	SYSAUX tablespace
1	500	UNDOTBS1 tablespace
1	250	TEMP tablespace
1	160	EXAMPLE tablespace
1	120	USERS tablespace
3	120	Three online redo log files
3	110	First and third control files
1	5	Server parameter file (SPFILE)
1	5	Password file

Execute the below command as root to create n number of logical volumes by executing the same command n number of times.
This will create n logical volumes named oracle_vg/lvol1 through oracle_vg/lvoln. Make sure that you change the size of logical
volume to match the appropriate file size. I executed

lvcreate -L sizem logical_grp_name

Where sizem represents the size of the volume in MB and
logical_grp_name represents the group name where this volume is created.

I have run this command 14 times to create 14 volumes for our test database files.

lvcreate -L 520m oracle_vg
lvcreate -L 520m oracle_vg
lvcreate -L 270m oracle_vg
lvcreate -L 170m oracle_vg
lvcreate -L 130m oracle_vg
lvcreate -L 130m oracle_vg
lvcreate -L 130m oracle_vg
lvcreate -L 130m oracle_vg
lvcreate -L 130m oracle_vg
lvcreate -L 130m oracle_vg
lvcreate -L 130m oracle_vg
lvcreate -L 8m oracle_vg
lvcreate -L 8m oracle_vg
lvcreate -L 520m oracle_vg

Run lvscan as root to get the information on volumes.

Binding Logical Volumes to the raw devices:

I have added the below lines into the /etc/sysconfig/rawdevices and restarted the rawdevices service to bind logical volumes

created in the above steps.


/usr/bin/raw /dev/raw/raw11 oracle_vg/lvol0    # test db -- SYSAUX Tablespace
/usr/bin/raw /dev/raw/raw12 oracle_vg/lvol1    # test db -- UNDOTBS1
/usr/bin/raw /dev/raw/raw13 oracle_vg/lvol2    # test db -- TEMP tablespace
/usr/bin/raw /dev/raw/raw14 oracle_vg/lvol3    # test db -- EXAMPLE tablespace
/usr/bin/raw /dev/raw/raw15 oracle_vg/lvol4    # test db -- USERS tablespace
/usr/bin/raw /dev/raw/raw16 oracle_vg/lvol5    # test db -- redo1_1.log
/usr/bin/raw /dev/raw/raw17 oracle_vg/lvol6    # test db -- redo1_2.log
/usr/bin/raw /dev/raw/raw18 oracle_vg/lvol7    # test db -- redo1_3.log
/usr/bin/raw /dev/raw/raw19 oracle_vg/lvol8    # test db -- control1
/usr/bin/raw /dev/raw/raw20 oracle_vg/lvol9    # test db -- control2
/usr/bin/raw /dev/raw/raw21 oracle_vg/lvol10    # test db -- control2	
/usr/bin/raw /dev/raw/raw22 oracle_vg/lvol11    # test db -- spfile
/usr/bin/raw /dev/raw/raw23 oracle_vg/lvol12    # test db -- pwfile
/usr/bin/raw /dev/raw/raw24 oracle_vg/lvol13    # test db -- SYSTEM Tablespace

Also, you need to change the ownership of these devices to oracle user. Raw devices are refreshed with the default
permissions and ownership every time you reboot your system. For this reason, I add these lines to the /etc/rc.local so
that every time machine reboots, this devices are assigned correct ownership/permissionsPlease add the below lines
to the /etc/rc.local

for i in `seq 1 25`
do
chown oracle:dba /dev/raw/raw$i
chmod 600 /dev/raw/raw$i
done

Creating dbca Raw Device Mapping File:

Creating Required directories:

Create a database file subdirectory under the Oracle base directory and set the appropriate owner, group and permissions on it.

[oracle@shree ~]$ mkdir -p $ORACLE_BASE/oradata/test
[oracle@shree ~]$ chown -R orcale:oinstall $ORACLE_BASE/oradata
[oracle@shree ~]$ chmod -R 755 $ORACLE_BASE/oradata
[oracle@shree ~]$ cd $ORACLE_BASE/oradata/test

Creating config file:

Create the test_raw.conf file under $ORACLE_BASE/oradata/test directory and add the below lines in it. This file is required by dbca when you
create the data using that. Manual method of creating database does not require this file.

system=/dev/raw/raw24
sysaux=/dev/raw/raw11
undotbs1=/dev/raw/raw12
temp=/dev/raw/raw13
example=/dev/raw/raw14
users=/dev/raw/raw15
redo1_1=/dev/raw/raw16
redo1_2=/dev/raw/raw17
redo1_3=/dev/raw/raw18
control1=/dev/raw/raw19
control2=/dev/raw/raw20
control3=/dev/raw/raw21
spfile=/dev/raw/raw22
pwdfile=/dev/raw/raw23

Linking raw devices: -- This is an OPTIONAL STEP

Optionally, You can create the softlink to the raw devices (e.g /dev/raw/raw10) to make this file recognize easily.
With the softlink created, file name as well as size can easily be guessed by looking at the link itself. Follow the
below steps to create the softlink and use them instead of device name.

[oracle@shree ~]$ ln -s /dev/raw/raw11 $ORACLE_BASE/oradata/test/test_sysaux_raw_520m
[oracle@shree ~]$ ln -s /dev/raw/raw12 $ORACLE_BASE/oradata/test/test_undotbs1_raw_520m
[oracle@shree ~]$ ln -s /dev/raw/raw13 $ORACLE_BASE/oradata/test/test_temp_raw_270m
[oracle@shree ~]$ ln -s /dev/raw/raw14 $ORACLE_BASE/oradata/test/test_example_raw_170m
[oracle@shree ~]$ ln -s /dev/raw/raw15 $ORACLE_BASE/oradata/test/test_users_raw_130m
[oracle@shree ~]$ ln -s /dev/raw/raw16 $ORACLE_BASE/oradata/test/test_redo1_1_raw_130m
[oracle@shree ~]$ ln -s /dev/raw/raw17 $ORACLE_BASE/oradata/test/test_redo1_2_raw_130m
[oracle@shree ~]$ ln -s /dev/raw/raw18 $ORACLE_BASE/oradata/test/test_redo1_3_raw_130m
[oracle@shree ~]$ ln -s /dev/raw/raw19 $ORACLE_BASE/oradata/test/test_control1_raw_130m
[oracle@shree ~]$ ln -s /dev/raw/raw20 $ORACLE_BASE/oradata/test/test_control2_raw_130m
[oracle@shree ~]$ ln -s /dev/raw/raw21 $ORACLE_BASE/oradata/test/test_control3_raw_130m
[oracle@shree ~]$ ln -s /dev/raw/raw22 $ORACLE_BASE/oradata/test/test_spfile_raw_8m
[oracle@shree ~]$ ln -s /dev/raw/raw23 $ORACLE_BASE/oradata/test/test_pwdfile_raw_8m
[oracle@shree ~]$ ln -s /dev/raw/raw24 $ORACLE_BASE/oradata/test/test_system_raw_520m

Now create the test_raw.conf file under $ORACLE_BASE/oradata/test directory and add the below lines in it.

system=/u01/app/oradata/test/test_system_raw_520m
sysaux=/u01/app/oradata/test/test_sysaux_raw_520m
undotbs1=/u01/app/oradata/test/test_undotbs1_raw_520m
temp=/u01/app/oradata/test/test_temp_raw_270m
example=/u01/app/oradata/test/test_example_raw_170m
users=/u01/app/oradata/test/test_users_raw_130m
redo1_1=/u01/app/oradata/test/test_redo1_1_raw_130m
redo1_2=/u01/app/oradata/test/test_redo1_2_raw_130m
redo1_3=/u01/app/oradata/test/test_redo1_3_raw_130m
control1=/u01/app/oradata/test/test_control1_raw_130m
control2=/u01/app/oradata/test/test_control2_raw_130m
control3=/u01/app/oradata/test/test_control3_raw_130m
spfile=/u01/app/oradata/test/test_spfile_raw_8m
pwdfile=/u01/app/oradata/test/test_pwdfile_raw_8m

Updating the .bash_profile:

Connect as a oracle user andf update the .bash_profile file with the new variable DBCA_RAW_CONFIG added into this. Again, this parameter is required
if you create the database through dbca.

The updated file should look like this:

#.bash_profile
# Get the aliases and functions
if [ -f ~/.bashrc ]; then
        . ~/.bashrc
fi
# User specific environment and startup programs

PATH=$PATH:$HOME/bin
export PATH
unset USERNAME
export ORACLE_BASE=/u01/app
export ORACEL_SID=test
export DBCA_RAW_CONFIG=$ORACLE_BASE/oradata/test_raw.conf
export ORACLE_HOME=$ORACLE_BASE/oracle/product/10.2.0/db_1
export PATH=$PATH:$ORACLE_HOME/bin
export LD_LIBRARY_PATH=$ORACLE_HOME/lib

Creating Database Manually without using dbca:

Once you complete the former steps (except creating config file and creating links), you are ready to create database manually.
Please follow the below steps.

create the password file:

[oracle@shree ~]$ orapwd file=$ORACLE_HOME/dbs/orapwtest password=changeIt entries=5

Create required directories:

[oracle@shree ~]$ mkdir -p $ORACLE_BASE/admin/test
[oracle@shree ~]$ cd $ORACLE_BASE/admin/test
[oracle@shree test]$ mkdir bdump
[oracle@shree test]$ mkdir udump
[oracle@shree test]$ mkdir cdump
[oracle@shree test]$ mkdir pfile

Create the inittest.ora file:

Using vi editor or any other editor you like, create the init+test.ora file under the $ORACLE_HOME/dbs
directory and add the below lines into this file.

db_cache_size=88080384
java_pool_size=4194304
large_pool_size=4194304
shared_pool_size=67108864
streams_pool_size=0
audit_file_dest='/u01/app/admin/test/adump'
background_dump_dest='/u01/app/admin/test/bdump'
compatible='10.2.0.1.0'
control_files='/dev/raw/raw19','/dev/raw/raw20','/dev/raw/raw21'
core_dump_dest='/u01/app/admin/test/cdump'
db_block_size=8192
db_domain=''
db_file_multiblock_read_count=16
db_name='test'
db_recovery_file_dest='/u01/app/flash_recovery_area'
db_recovery_file_dest_size=2147483648
dispatchers='(PROTOCOL=TCP) (SERVICE=testXDB)'
job_queue_processes=10
open_cursors=300
pga_aggregate_target=16777216
processes=150
remote_login_passwordfile='EXCLUSIVE'
sga_target=167772160
undo_management='AUTO'
undo_tablespace='UNDOTBS1'
user_dump_dest='/u01/app/admin/test/udump'

Create spfiletest.ora and start the instance using that file:

[oracle@shree ~]$ export ORACLE_SID=test
[oracle@shree ~]$ sqlplus / as sysdba

SQL*Plus: Release 10.2.0.1.0 - Production on Thu Dec 8 22:06:29 2005

Connected to an idle instance.

SQL> create spfile from pfile;

File created.

Run the CREATE DATABASE command:

Now ruu the $ORACLE_HOME/rdbms/admin/catalog.sql and $ORACLE_HOME/rdbms/admin/catproc.sql.

Creating Database using dbca:

Please follw these steps to crete the database using dbca that uses raw devices as storage options.

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REFERENCES:

Oracle Documents