[CentOS] free memory listing

Hi,

I have two 64 bit cent Os machine. I googled that in linux always show
entire memory as used. But below showing only 1 GB  detected.


*Machine 1  :*
i) It has 31 GB of ram.

[root at machine1]# free -g
                 total       used       free     shared    buffers
cached
Mem:            31          1         30          0          0          0
-/+ buffers/cache:          0         30
Swap:           49          0         49
------------------------------------------

*Machine 2 :*
i)It has 11 GB of ram.

[root at machine2]# free -g
                  total       used       free     shared    buffers
cached
Mem:            11         11          0          0          0          9
-/+ buffers/cache:        1         10
Swap:           49          0         49


Could you please anyone can explain why ?


Thanks,
Ashik
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