从Oracle 11.2开始，一个ASM磁盘组可以被用来创建一个或多个集群文件系统。这就是Oracle ASM集群文件系统或Oracle ACFS。这个功能通过在ASM磁盘组中创建特定的volume文件来实现，然后作为块设备给操作系统来使用，再在这些块设备上创建文件系统。下面将介绍ACFS volume文件的rebalance,mirror与extent管理。
测试环境如下:
.64-bit Oracle Linux 5.4
.Oracle Restart and ASM version 11.2.0.4.0 - 64bit
设置ACFS volumes
单实例加载ADVM/ACFS驱动的命令如下，RAC环境不需要，因为已经默认加载
[root@jyrac1 bin]# ./acfsroot install
ACFS-9300: ADVM/ACFS distribution files found.
ACFS-9118: oracleadvm.ko driver in use - cannot unload.
ACFS-9312: Existing ADVM/ACFS installation detected.
ACFS-9118: oracleadvm.ko driver in use - cannot unload.
ACFS-9314: Removing previous ADVM/ACFS installation.
ACFS-9315: Previous ADVM/ACFS components successfully removed.
ACFS-9307: Installing requested ADVM/ACFS software.
ACFS-9308: Loading installed ADVM/ACFS drivers.
ACFS-9321: Creating udev for ADVM/ACFS.
ACFS-9323: Creating module dependencies - this may take some time.
ACFS-9154: Loading 'oracleacfs.ko' driver.
ACFS-9327: Verifying ADVM/ACFS devices.
ACFS-9156: Detecting control device '/dev/asm/.asm_ctl_spec'.
ACFS-9156: Detecting control device '/dev/ofsctl'.
ACFS-9309: ADVM/ACFS installation correctness verified.
[root@jyrac1 bin]# ./acfsload start
ACFS-9391: Checking for existing ADVM/ACFS installation.
ACFS-9392: Validating ADVM/ACFS installation files for operating system.
ACFS-9393: Verifying ASM Administrator setup.
ACFS-9308: Loading installed ADVM/ACFS drivers.
ACFS-9327: Verifying ADVM/ACFS devices.
ACFS-9156: Detecting control device '/dev/asm/.asm_ctl_spec'.
ACFS-9156: Detecting control device '/dev/ofsctl'.
ACFS-9322: completed
[root@jyrac1 bin]# ./acfsdriverstate version
ACFS-9325: Driver OS kernel version = 2.6.18-8.el5(x86_64).
ACFS-9326: Driver Oracle version = 130707.
创建一个用来创建ASM集群文件系统的磁盘组
SQL> create diskgroup acfs disk '/dev/raw/raw5','/dev/raw/raw6' attribute 'COMPATIBLE.ASM' = '11.2', 'COMPATIBLE.ADVM' = '11.2';
Diskgroup created.
虽然一个磁盘组可以用来存储数据库文件与ACFS volume files，但是建议为ACFS volume创建一个单独的磁盘组。这将提供角色/功能分离与对数据库文件性能有潜在好处。
检查所有磁盘组的AU大小
SQL> select group_number "Group#", name "Name", allocation_unit_size "AU size" from v$asm_diskgroup_stat;
Group# Name AU size
---------- ------------------------------------------------------------ ----------
1 ARCHDG 1048576
2 CRSDG 1048576
3 DATADG 1048576
4 ACFS 1048576
对于所有磁盘组来说缺省的AU大小为1MB，当后面介绍volume file的区大小时会使用到AU大小。
在磁盘组ACFS中创建三个volume
[grid@jyrac1 ~]$ asmcmd volcreate -G ACFS -s 1G ACFS_VOL1
[grid@jyrac1 ~]$ asmcmd volcreate -G ACFS -s 1G ACFS_VOL2
[grid@jyrac1 ~]$ asmcmd volcreate -G ACFS -s 1G ACFS_VOL3
查看volume信息
[grid@jyrac1 ~]$ asmcmd volinfo -a
Diskgroup Name: ACFS
Volume Name: ACFS_VOL1
Volume Device: /dev/asm/acfs_vol1-10
State: ENABLED
Size (MB): 1024
Resize Unit (MB): 32
Redundancy: MIRROR
Stripe Columns: 4
Stripe Width (K): 128
Usage:
Mountpath: