Hi , This doc should make the memory calculations clear to you.
https://cwiki.apache.org/confluence/display/CLOUDSTACK/CPU+and+RAM+Overcommit Thanks, Bharat. On 16-Apr-2015, at 3:24 pm, 蔡高扬 <[email protected]<mailto:[email protected]>> wrote: When I changed the value of “mem.overprovisioning.factor” in a cluster, i.e. from 1 to 2, the used memory value in dashboard also changed (in this example, doubled) as well as total momory. After I shut down VMs in the cluster and start them, memory usage became correct. I found the code calculating the used momory but couldn’t understand the way to calculating and updating this value. In com.cloud.capacity.CapacityManagerImpl.updateCapacityForHost(Host): =================================================================== usedMemory += ((so.getRamSize() * 1024L * 1024L)/ramOvercommitRatio)*clusterRamOvercommitRatio; =================================================================== In the code above, clusterRamOvercommitRatio updates instantly after overprovisioning factor sets, but ramOvercommitRatio only updates according to clusterRamOvercommitRatio when VM starts. This leads to inconsistency between the two variables. So my question is: 1. Why calculating usedMemory in such way (devided by ramOvercommitRatio and then multiplied clusterRamOvercommitRatio)? 2. Why NOT updating ramOvercommitRatio when overprovisioning factor changes, until when VM starts? 3. How to fix incorrect memory usage without restarting VMs ? Thanks. Kelvin Cai, Ping An Technology (Shenzhen) Co., Ltd. | Infrastructure. ******************************************************************************************************************************** The information in this email is confidential and may be legally privileged. If you have received this email in error or are not the intended recipient, please immediately notify the sender and delete this message from your computer. Any use, distribution, or copying of this email other than by the intended recipient is strictly prohibited. All messages sent to and from us may be monitored to ensure compliance with internal policies and to protect our business. Emails are not secure and cannot be guaranteed to be error free as they can be intercepted, amended, lost or destroyed, or contain viruses. Anyone who communicates with us by email is taken to accept these risks. 收发邮件者请注意： 本邮件含保密信息，若误收本邮件，请务必通知发送人并直接删去，不得使用、传播或复制本邮件。 进出邮件均受到本公司合规监控。邮件可能发生被截留、被修改、丢失、被破坏或包含计算机病毒等不安全情况。 ********************************************************************************************************************************
