thornef
Contributor
Contributor

Host/Guest Usage Memory

Hi,

I have an evaluation copy of ESX server 3 and was hoping some one might be able to explain the diference between Host and Guest memory usage when it is displayed in VirtualCeter 2 on the summary of the Virtual Machine

Thanks

Francis

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4 Replies
TomHowarth
Leadership
Leadership

Have a read of this thread it will give you an overview

http://www.vmware.com/community/message.jspa?messageID=460945&tstart=0

Tom Howarth VCP / VCAP / vExpert
VMware Communities User Moderator
Blog: http://www.planetvm.net
Contributing author on VMware vSphere and Virtual Infrastructure Security: Securing ESX and the Virtual Environment
Contributing author on VCP VMware Certified Professional on VSphere 4 Study Guide: Exam VCP-410
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thornef
Contributor
Contributor

Thanks for the link,

I'm starting to get an understanding but I am a bit confussed by what the Virtual Center is showing me.

For example under Host I get the following displayed.

Summary

2GB memory used

Virtual Machine

Host Mem Guest % Guest Mem

Server 1 348 1 0

Server 2 497 2 50

Server 3 497 48 250

Resource Allocation

Memory Reservation 3363MB

Memory Reservation Used 134MB

Memory Reservation not used 3327

Configurartion - Memory

Total 4GB

System 330MB

Service Console 272MB

Virtual Machine 3.41 GB

Problem i have is i just dont see how some of these numbers add up, i.e. the 2GM memory used in summary and then only 134MB reservation used ?

Any help would be really appricated.

Thanks in advance

Francis

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kitcolbert
VMware Employee
VMware Employee

Memory reservation is a separate idea/system from memory usage. Usage obviously refers to how much host memory the VM is actually using. Reservation is how much host memory the VM is guaranteed to get. Reservation is also an admission control system. If there is not enough unreserved host memory to meet the reservation requirement for the VM, then the VM will fail to power on.

Thus it may be the case that a VM has a 1 gig memory reservation, but it's using 2 gigs of host memory. Or it may also be that it has a 1 gig memory reservation, but it's only using 500 megs of host memory. The numbers are somewhat independent, and thus don't have to add up.

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hernanm
Contributor
Contributor

I'm trying to determine the best balance for optimal performance. I have a 4gb RAM system. I'm using the FIT ALL VIRTUAL MACHINE MEMORY INTO RESERVED and I have disable the MEMORY TRIM option for each virtual machine. 1GB is reserved for the host. I have 6 VM running in total.

Everything is running pretty gud, but I noticed some swap on the host.

Is the amout of memory reserved for the host enough? (Im using the default value). Should I increase it?

Regards,

Hernán.

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