OS

Configuration of Oracle ASMlib disks in GNU/Linux

Posted on by Didac Oliveira

 

ASMLib is a support library for the Automatic Storage Management feature of the Oracle Database.
Simplifies database administration and reduces kernel resource usage, but some configurations in the OS disks should be done before ASMlib will work as pretended.

This article will explain the configuration of ASMlib disks in GNU/Linux systems in order to ASM can manage them.
Oracle ASM software should be installed and properly configured previously, see note details.

Note

ASMlib download page:
http://www.oracle.com/technetwork/server-storage/linux/asmlib/index-101839.html
ASMlib base configuration:
http://www.oracle.com/technetwork/server-storage/linux/install-082632.html

We will configure the following system disks to be used by ASMlib:

GNU/Linux Device Name ASM label
/dev/mapper/asmdisk_01 ORA_ASM_DISK01
/dev/mapper/asmdisk_02 ORA_ASM_DISK02

Creating Partitions (any node)

First of all we will partition the disks:

Using fdisk:

$ for i in 01 02; do echo -e "o\nn\np\n1\n\n\nw" | fdisk /dev/mapper/asmdisk_$i; done

Using parted:

$ for i in 01 02; do parted -s -a optimal /dev/mapper/asmdisk_$i mklabel gpt mkpart primary 0% 100%; done

Check parititons (any node)

Now, check if partitions were created correctly.

Using fdisk:

$ for i in 01 02; do fdisk -l /dev/mapper/asmdisk_$i; done

...
                  Device Boot      Start         End      Blocks   Id  System
/dev/mapper/asmdisk_01p1               1      104433   838858041   83  Linux

...
                    Device Boot      Start         End      Blocks   Id  System
/dev/mapper/asmdisk_02p1               1       26108   209712478+  83  Linux

Using parted:

$ for i in 01 02; do parted /dev/mapper/asmdisk_$i print; done

...
Disk /dev/mapper/asmdisk_01: 85900MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number  Start   End     Size    File system   Name     Flags
 1      1049kB  85.9GB  85.9GB                primary
...
Disk /dev/mapper/asmdisk_02: 85900MB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Number  Start   End     Size    File system   Name     Flags
 1      1049kB  85.9GB  85.9GB                primary

Load partitons (all nodes)

The partitions must be loaded on all node’s kernel to properly label them with ASMlib.

$ for i in 01 02; do kpartx -a /dev/mapper/asmdisk_$i; done

Check loaded parts (all nodes)

$ for i in 01 02; do kpartx -l /dev/mapper/asmdisk_$i; done

asmdisk_01p1 : 0 1677716082 /dev/mapper/asmdisk_01 63
asmdisk_02p1 : 0 419424957 /dev/mapper/asmdisk_02 63

Label ASM disks (any node)

If partitions were loaded correctly in all nodes, we will label the partitions in ASMlib:

$ for i in 01 02; do /etc/init.d/oracleasm createdisk ORA_ASM_DISK${i} /dev/mapper/asmdisk_${i}p1; done

Marking disk "ORA_ASM_DISK01" as an ASM disk:             [  OK  ]
Marking disk "ORA_ASM_DISK02" as an ASM disk:             [  OK  ]

$ oracleasm listdisks

ORA_ASM_DISK01
ORA_ASM_DISK02

Scan/List ASM disks (other nodes)

$ oracleasm scandisks

Reloading disk partitions: done
Cleaning any stale ASM disks...
Scanning system for ASM disks...
Instantiating disk "ORA_ASM_DISK01"
Instantiating disk "ORA_ASM_DISK02"

$ oracleasm listdisks

ORA_ASM_DISK01
ORA_ASM_DISK02

Conclusion

Hope this short How-To article will be useful to any GNU/Linux SysAdmin and/or DBA using Oracle ASM with ASMlib.