ASM Supported Storage Resources

 

ASM Supported Storage Resources

To create ASM diskgroup you need valid asm disks. Following are the storage resources supported by ASM for ASM disks to create a diskgroup

Disk Partition: A disk partition can be the entire disk drive or a section of a disk drive. It must not be formated (ie should not includes the partition table)

Logical Unit Number (LUN): A LUN is a disk presented to a computer system by a storage array.

Logical Volume: Although Logical Volumes are supported by ASM it is not recommended by Oracle.

Network File System (NFS):An Oracle ASM disk group can be created from NFS files, including Oracle Direct NFS (dNFS). The NFS files that are provisioned to a disk group may be from multiple NFS servers to provide better load balancing and flexible capacity planning.
You can use NFS, with or without Direct NFS, to store data files. However, NFS is not supported for Oracle Clusterware files.
NFS-based quorum disks (quorum failure groups) should not use Direct NFS (dNFS) because dNFS does not support soft mounts.

Preparing Disks for ASM

• Change the user and group ownership of devices to oracle:oinstall

oracle:is Owner of asm binaries
oinstall: Primary group of user oracle
chown -R oracle:oinstall /dev/xvdd
chown -R oracle:oinstall /dev/xvde

• Change the device permissions to read/write

chmod 660 /dev/xvdd
chmod 660 /dev/xvde

Note:- On older Linux versions, you must configure raw device binding (ie you need to configure /etc/sysconfig/rawdevices), if you are not using asmlib
Installing configuring and preparing ASM disks using ASMLIB is covered in another post.

• Change asm_diskstring parameter to allow ASM to search the disk. for Example If the all the disks are located under /dev/ and named like xvd[something] then the value of asm_diskstring would be /dev/xvd*

Note: Login to ASM instance as sysasm to change the asm_diskstring parameter

$ export ORACLE_SID=+ASM
$ export ORACLE_HOME=/u01/oracle/grid_122