How to setup ACFS manually

You can use ASMCA to setup ACFS, below are the steps to 
setup it manually:

Create Diskgroups

1 CREATE DISKGROUP ACFS_DATA EXTERNAL REDUNDANCY
2 DISK 'ORCL:ACFSVOL1' NAME ACFSVOL1
3 ATTRIBUTE 'au_size'='1M',
4 'compatible.asm' = '11.2',
5 'compatible.rdbms' = '11.2',
6 'compatible.advm' = '11.2';

Load ACFS Drivers

Validate ACFS drivers, 
#lsmod |grep oracle 
oracleacfs           1734520  0 
oracleadvm            242048  0 
oracleoks             295248  2 oracleacfs,oracleadvm 
oracleasm              84136  1 

If you don't see oracleacfs, oracleadvm and oracleoks, load the ACFS Driver:

$GRID_HOME/bin/acfsload start –s

Create the Dynamic volume on ACFS
1 sqlplus / as sysasm 
2 alter diskgroup ACFS_DATA add volume acfsvol_01 size 100G;
3  
4 select VOLUME_NAME, VOLUME_DEVICE from v$asm_volume;
5  
6 VOLUME_NAME                    VOLUME_DEVICE
7 ------------------------------ ------------------------------
8 ACFSVOL_01                     /dev/asm/acfsvol_01-335

Create Filesystem for ACFS Volume Device
As root user, to create a filesystem on linux for the ACFS volume device

mkfs -t acfs -b 4k /dev/asm/acfsvol_01-335
mkfs.acfs: version                   = 11.2.0.1.0.0
mkfs.acfs: on-disk version           = 39.0
mkfs.acfs: volume                    = /dev/asm/acfsvol_01-335
mkfs.acfs: volume size               = 268435456

Mount ACFS Filesystem

mkdir -p /datapump

mount -t acfs /dev/asm/acfsvol_01-335 /datapump

chown oracle:oinstall /datapump

df -h to verify.

Oracle ACFS Mount Registry
Register ACFS mount point to automatic startup ACFS mount devices

acfsutil registry -a /dev/asm/acfsvol_01-335 /datapump