virtual machines with low CPU but high memory(%) utilization

[PandzicM]

Hello,

trying to resolve (and better understand) why  in Cluster containing two hosts (HP proliant DL 585 G7) running ESXi 6.0 U2 and 16 VMs(mix of oracle solaris 10(64 bit),Red Heat 7,Cisco expressway/VCS Base,Websphere Datapower,W2K12 64 bit) see CPU% is between 0-3  and Memory% is at 83% and on other host CPU% is 0 and Memory% is 50%.

Two VMs with considerable higher Memory% utilization are those tvo Cisco appliances.

Is it fair to say that some general explanation exist as why we can see low CPU but high memory utilization on ESXi hosts? Understandably each environment is differently set up but any suggestion/explanation would be appreciated.

Thanks

[daphnissov]

Have you looked at the VMs running on each host to see what vSphere reports their CPU utilization as? Does it roughly line up with what the entire host is reporting? If you have giant hosts with dense cores, 3% may be a substantial amount of cycles. Then again, if these VMs are largely idle with CPU and not doing much, that could be entirely accurate.

[PandzicM]

Hi

Thanks for quick reply

VMs with higher mem utilization ran on one host and looks like this is aligned with what host is reporting.

I do not have access to these VMs to actually see if they are idling or not.

If you can explain how much cores on one host is amount to consider as "dense cores" hardware? I am new to VMware and would like to learn as much I can get.

Thanks

[PandzicM]

forgot to mention:

each of these two hosts have 4 proc sockets, cores per socket=12 and logical processors=48