How to Partition disks, Create Oracle ASM disks and Create Oracle ASM Disk group

(Please Note my other blog address: svgulhane wordpress IT updates)

Simple Steps to Create ASM Diskgroup:

• Disk requirement from Storage team

Contact the Storage team for shared space across the cluster nodes and request shared OS disks for clusterware nodes.

There are many type of LUN storages (Pillar/Axiom/NAS/FS) request as per your requirement for project.

Example:
/dev/mapper/3600144f0c8f21f48000052e8a4b80001

• Login  and verify the assigned shared storage disks

Example of OS disk of size 322 GB given by storage team

[root@exampleserver1 bin]# /sbin/fdisk -l /dev/mapper/3600144f0c8f21f48000052e8a4b80001

Disk /dev/mapper/3600144f0c8f21f48000052e8a4b80001: 322.1 GB, 322122547200 bytes

255 heads, 63 sectors/track, 39162 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk identifier: 0x00000000

Listing different types of Storage

multipath -ll | grep Pillar

multipath -ll|grep FS1

multipath -ll | grep ZFS

• Partition the Disk

[root@exampleserver1 ~]# /sbin/fdisk /dev/mapper/3600144f0c8f21f48000052e8a4b80001

Command (m for help): u

Changing display/entry units to sectors

Command (m for help): n

Command action

   e   extended

   p   primary partition (1-4)

p

Partition number (1-4): 1

First sector (63-629145599, default 63): 2048

Last sector, +sectors or +size{K,M,G} (2048-629145599, default 629145599):

Using default value 629145599

Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.

WARNING: Re-reading the partition table failed with error 22: Invalid argument.

The kernel still uses the old table. The new table will be used at

the next reboot or after you run partprobe(8) or kpartx(8)

Syncing disks

• Verify the Partitioned disk

[root@exampleserver1 ~]# /sbin/fdisk -l /dev/mapper/3600144f0c8f21f48000052e8a4b80001

Disk /dev/mapper/3600144f0c8f21f48000052e8a4b80001: 322.1 GB, 322122547200 bytes

255 heads, 63 sectors/track, 39162 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Sector size (logical/physical): 512 bytes / 512 bytes

I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk identifier: 0x1763aba7

Device Boot      Start         End      Blocks   Id  System

/dev/mapper/3600144f0c8f21f48000052e8a4b80001p1               1       39163   314571776   83  Linux

Now disk can be recognized by ASM

Run on the server where partition was created

/sbin/partprobe

• Create the ASM Disk from partitioned disk:

[root@exampleserver1 oracleasm]#  /usr/sbin/oracleasm createdisk ISC300GGCW01 /dev/mapper/3600144f0c8f21f48000052e8a4b80001p1

Writing disk header: done

Instantiating disk: done

[root@exampleserver1 oracleasm]# /usr/sbin/oracleasm scandisks

Reloading disk partitions: done

Cleaning any stale ASM disks...

Scanning system for ASM disks...

Instantiating disk "ISC300GGCW01"

[root@exampleserver1 bin]# /usr/sbin/oracleasm listdisks

ISC300GGCW01

Run on other node exampleserver2 to check the ASM disk existence:

/usr/sbin/oracleasm scandisks

[root@exampleserver2 bin]# /usr/sbin/oracleasm scandisks

Reloading disk partitions: done

Cleaning any stale ASM disks...

Scanning system for ASM disks...

Instantiating disk "ISC300GGCW01"

[root@exampleserver2 bin]# /usr/sbin/oracleasm listdisks

ISC300GGCW01

• Create Diskgroup by using ASM Disk(s)

Now we have the ASM disk, now we can go to create the ASM diskgroup with very simple way by using vncserver or xmanager to get GUI of asmca

By login to grid OS user, execute asmca command as follows:

Setting Grid home

[grid@exampleserver1 bin]# . oraenv

+ASM1

[grid@exampleserver1 bin]# asmca

Here we have selected the available provisioned disk and used the provided name for diskgoup and created the diskgroup by selecting the External type of Diskgroup, for this only one disk can be used.

Thanks and Regards

Santoshkumar Gulhane

(Please Note my other blog address: svgulhane wordpress IT updates)