Oracle Magazine - September/October 2010

To perform the check, he issues the following SQL:

SQL> select compatibility, database_compatibility

2 from v$asm_diskgroup 3 where name = 'ACFSDG1';

Code Listing 1: Using mkfs to create the file system

mkfs -t acfs -b 4k /dev/asm/acfsvol1a-153 mkfs.acfs: version = 11. 2.0.1.0.0 mkfs.acfs: on-disk version = 39.0 mkfs.acfs: volume = /dev/asm/acfsvol1a-153 mkfs.acfs: volume size = 1073741824 mkfs.acfs: Format complete.

COMPATIBILITY DATABASE_COMPATIBILITY ————————————————— —————————————————————————————— 11. 2.0.0.0 11. 2.0.0.0

If the result had shown something other than 11. 2, he would have had to set the compatibility to 11. 2 by issuing the following series of SQL statements:

SQL> alter diskgroup acfsdg1 set attribute 'compatible.asm' = ' 11. 2';

Code Listing 2: Verifying that the file system is mounted

mount /dev/mapper/VolGroup00-LogVol00 on / type ext3 (rw) proc on /proc type proc (rw) sysfs on /sys type sysfs (rw) devpts on /dev/pts type devpts (rw,gid= 5,mode=620) /dev/sda1 on /boot type ext3 (rw) tmpfs on /dev/shm type tmpfs (rw) none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw) sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw) /dev/asm/acfsvol1-153 on /acfsdir1 type acfs (rw)

Diskgroup altered.

SQL> select volume_name, volume_device 2 from v$asm_volume;

directory named /acfsdir1, as the root user, as shown below.

SQL> alter diskgroup acfsdg1 set attribute 'compatible.rdbms' = ' 11. 2';

Diskgroup altered.

SQL> alter diskgroup acfsdg1 set attribute 'compatible.advm' = ' 11. 2';

Diskgroup altered.

Next John creates the Oracle Automatic Storage Management dynamic volume. He mentions the four different ways to accomplish this task: using regular SQL statements, using the ASMCMD command line, using the ASMCA utility, and using Oracle Enterprise Manager. To keep it simple, John shows everyone the approach that involves regular SQL.

To create a 10 MB volume called ACFSVOL1A, John issues the following SQL:

alter diskgroup acfsdg1 add volume acfsvol1a size 10M;

Afterward he confirms that the volume was correctly created, by checking a view called V$ASM_VOLUME, in which the volume will appear if it was created successfully. The following query confirms that the volume was successfully created:

VOLUME_NAME VOLUME_DEVICE ——————————————— ————————————————————————————— ACFSVOL1A /dev/asm/acfsvol1a-153 ACFSVOL1B /dev/asm/acfsvol1b-153

CREATING AN ORACLE AUTOMATIC
STORAGE MANAGEMENT CLUS TER
FILE SYS TEM

The preceding ALTER DISKGROUP statement initiated an action that created an Oracle Automatic Storage Management dynamic volume file as well as an associated Linux dynamic volume device that is directly addressable by the operating system. (The name of the device is shown in the VOLUME_DEVICE column of the V$ASM_VOLUME view.) This device enables Linux to identify the Oracle Automatic Storage Management volume as a device and makes it possible to create a file system on the volume by using the mkfs command. John demonstrates this by issuing the command shown in Listing 1 to create a file system on the Oracle Automatic Storage Management volume.

The -t flag in the mkfs statement indicates that the file system should be of type acfs. Note that although the mkfs statement prepared the volume to be mounted as a file system, it did not actually mount it. To mount the file system, John first creates a

mkdir -p /acfsdir1

He then mounts the file system /acfsdir1, using the regular Linux mount command:

mount -t acfs /dev/asm/acfsvol1a-153 /acfsdir1

To verify that the file system was mounted properly, he then uses the mount command shown in Listing 2.

The output clearly shows that Linux has mounted the file system /acfsdir1. Once the file system is mounted, users can access /acfsdir1 as a regular file system. John then changes the directory ownership to oracle by issuing the following Linux command:

chown oracle:dba /acfsdir1

With this command, the oracle user can now read from and write to this file system. Furthermore, because Oracle Automatic Storage Management Cluster File System is a regular file system, any application can now access files on this file system without any special access mechanisms.