File size under linux

Users Badger
1

I am writing a small program to test Badger, just added 26 keys (content read from /proc/cpuinfo), and list the directory contents in bash:

... ...
-rw-rw-r-- 1 fxr fxr 2147483646  9月 27 22:17 000027.vlog
-rw-rw-r-- 1 fxr fxr       1687  9月 27 22:16 000028.sst
-rw-rw-r-- 1 fxr fxr       1896  9月 27 22:16 00025.mem
-rw-rw-r-- 1 fxr fxr       1896  9月 27 22:17 00026.mem
-rw-rw-r-- 1 fxr fxr  134217728  9月 27 22:17 00027.mem
-rw-rw-r-- 1 fxr fxr    1048576  9月 27 21:24 DISCARD
-rw------- 1 fxr fxr         28  9月 27 21:24 KEYREGISTRY
... ...
fxr@office:~/git/badger/badger-test$ du -sh
116K    .

There are several huge files, but the total size reported by du is just 116K, why?