修改/etc/fstab文件，假设挂载到/data目录，在最后一行加上

/dev/sdb1      /data                            ext4    defaults        1 1

#
# /etc/fstab
# Created by anaconda on Thu Sep 11 04:12:21 2014
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root /                       xfs     defaults        1 1
UUID=bf755645-8a3b-4222-9278-7747b8e89ce4 /boot                   xfs     defaults        1 2
/dev/mapper/centos-swap swap                    swap    defaults        0 0
/dev/sdb1      /data                            ext4    defaults        1 1

Linux自动挂载第二块硬盘分区