COMPUTER SCIENCE AND ENGINEERING
CLOUD COMPUTING
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Memory overcommitment technologies include memory ballooning, memory swapping, and memory sharing.
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Memory overcommitment technologies allow the total memory size of VMs to be greater than the total memory size of the physical server.
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After memory overcommitment is enabled, the memory overcommitment ratio is inversely proportional to the actual memory usage of each VM
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Memory overcommitment technologies allow the used memory size of VMs to be greater than the total memory size of the physical server.
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Detailed explanation-1: -Memory overcommitment allows a VM to use more memory space than the physical host has. Commonly used technologies include memory ballooning, memory sharing, and memory swapping.
Detailed explanation-2: -This section describes the techniques VMware Cloud on AWS uses to allow memory overcommitment. VMware Cloud on AWS uses four memory management mechanisms to dynamically reduce the amount of machine physical memory required for each virtual machine. These are page sharing, ballooning, memory compression, and swapping.
Detailed explanation-3: -We recommend 1:2 overcommit ratio between physical RAM and virtual RAM. Going above this is risky. Memory Usage on most of your clusters is high, around 90%. You should aim for 60% as you need to consider HA.
Detailed explanation-4: -Memory is overcommitted when the combined working memory footprint of all virtual machines exceed that of the host memory sizes. Because of the memory management techniques the ESXi host uses, your virtual machines can use more virtual RAM than there is physical RAM available on the host.