<div dir="ltr">Hi,<div><br></div><div>I launched an AWS instance `t2.medium` (use CentOS 7 image &quot;ami-7abd0209<span style="line-height:1.5">&quot;, product code: </span><a href="https://aws.amazon.com/marketplace/pp/B00O7WM7QW">https://aws.amazon.com/marketplace/pp/B00O7WM7QW</a><span style="line-height:1.5">), which is supposed to have 4GB Memory in total, but turn out it is only &quot;3.5GB&quot;. </span></div><div><br></div><div>```</div><div><div>$ free -h</div><div>              total        used        free      shared  buff/cache   available</div><div>Mem:           3.5G        441M        1.4G         16M        1.6G        2.7G</div><div>Swap:            0B          0B          0B</div></div><div>```</div><div><br></div><div>It does not happen to AWS Ubuntu 16.04.</div><div><br></div><div>```</div><div>$ free -h</div><div><div>              total        used        free      shared  buff/cache   available</div><div>Mem:           3.9G         49M        3.3G        5.5M        518M        3.7G</div><div>Swap:            0B          0B          0B</div></div><div>```</div><div><br></div><div>This seems to happen to all AWS CentOS image, regardless which instance type it is.</div></div>