root@debian8:~# tune2fs -l /dev/vg00/ext4fs 
tune2fs 1.42.12 (29-Aug-2014)
Filesystem volume name:   <none>
Last mounted on:          /mnt/ext4fs
Filesystem UUID:          13a7db21-8940-4bd2-a4b0-9cdedb8958ad
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
Filesystem flags:         signed_directory_hash 
Default mount options:    user_xattr acl
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              3932160
Block count:              15728640
Reserved block count:     786432
Free blocks:              15435821
Free inodes:              3932149
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      1020
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         8192
Inode blocks per group:   512
Flex block group size:    16
Filesystem created:       Fri Jul  3 11:08:15 2015
Last mount time:          Fri Jul  3 11:09:29 2015
Last write time:          Fri Jul  3 11:09:29 2015
Mount count:              2
Maximum mount count:      -1
Last checked:             Fri Jul  3 11:08:15 2015
Check interval:           0 (<none>)
Lifetime writes:          1092 MB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:	          256
Required extra isize:     28
Desired extra isize:      28
Journal inode:            8
Default directory hash:   half_md4
Directory Hash Seed:      7dca7cf5-cea9-4354-b38d-f833c56bb09a
Journal backup:           inode blocks