Configuring Files on an NAS Device for Use with ASM

To use an NFS file system, it must be on a certified NAS device. If you have a certified network attached storage (NAS) device, then you can create zero-padded files in an NFS mounted directory and use those files as disk devices in an ASM disk group.

To ensure high availability of Oracle Clusterware files on ASM, you need to have at least 2 GB of disk space for Oracle Clusterware files in three separate failure groups, with at least three physical disks. Each disk must have at least 1 GB of capacity to ensure that there is sufficient space to create Oracle Clusterware files.

Use the following guidelines when identifying appropriate disk devices:

• All of the devices in an Automatic Storage Management disk group should be the same size and have the same performance characteristics.

• A disk group should not contain more than one partition on a single physical disk device.

• Using logical volumes as a device in an Automatic Storage Management disk group is not supported with Oracle RAC.

• The user account with which you perform the installation (oracle) must have write permissions to create the files in the path that you specify.

To configure NAS device files for creating disk groups:

1. If necessary, create an exported directory for the disk group files on the NAS device.

   Refer to the NAS device documentation for more information about completing this step.

2. Switch to the root user.

3. Create a mount point directory on the local system. For example:

   # mkdir -p /mnt/oracleasm
   

4. To ensure that the NFS file system is mounted when the system restarts, add an entry for the file system in the mount file /etc/fstab.

   For more information about editing the mount file for the operating system, refer to the Linux man pages. For more information about recommended mount options, refer to Oracle Grid Infrastructure Installation Guide for Linux.

5. Enter a command similar to the following to mount the NFS file system on the local system:

   # mount /mnt/oracleasm
   

6. Choose a name for the disk group that you want to create, for example, sales1.

7. Create a directory for the files on the NFS file system, using the disk group name as the directory name, for example:

   # mkdir /mnt/oracleasm/sales1
   

8. Use commands similar to the following to create the required number of zero-padded files in this directory:

   # dd if=/dev/zero of=/mnt/oracleasm/nfsdg/disk1 bs=1024k count=1000
   

   This example creates 1 GB files on the NFS file system. You must create one, two, or three files respectively to create an external, normal, or high redundancy disk group.

9. Enter the following commands to change the owner, group, and permissions on the directory and files that you created:

   # chown -R oracle:dba /mnt/oracleasm
   # chmod -R 660 /mnt/oracleasm
   

10. When installing Oracle RAC, when creating an ASM disk group, edit the disk discovery string to specify a regular expression that matches the file names you created, for example, /mnt/oracleasm/sales1.

    Note: To simplify the ASM administration of disks, you can install the Linux ASMLIN RPMs, as described in Oracle Grid Infrastructure Installation Guide for Linux.