hadoop_disk_format.sh

vi /etc/mke2fs.conf
#add to /etc/mke2fs.conf :
hadoop = {
                   features = has_journal,extent,huge_file,flex_bg,uninit_bg,dir_nlink,extra_isize
                   inode_ratio = 131072
                   blocksize = -1
                   reserved_ratio = 0
                   default_mntopts = acl,user_xaddr
          }
##for all 12 disks

echo y | mkfs.ext4 -T hadoop /dev/sdb &
mkdir /data1
mount /dev/sdb  /data1  -o inode_readahead_blks=128,data=writeback,noatime,nodev,nobarrier

vi /etc/fstab
#on /etc/fstab:
/dev/sdb               /data1                 ext4  data=writeback,noatime,nodev,nobarrier  0 1