What is the difference between VM-utilized memory and consumed memory?
a VM appears in a management system to have a low utilized memory (25% or less), while it has a very high consumed memory.
There's quite a nice blog post here on performance metrics... https://www.datadoghq.com/blog/vsphere-metrics/
In order for a VMKernel to accurately discern how much memory is actively in use by VMs, it would need to monitor every memory page that has been read from or written to. This process, however, would require too much overhead. Instead, the VMKernel uses algorithmic learning to generate an estimate of each VM’s active memory usage. The VMKernel reports this estimate, measured in KBs, as the mem.active metric. Consumed memory, measured by the mem.consumed metric, represents the amount of an underlying host’s memory that’s allocated to a VM.
Active memory is a good real-time gauge of your VMs’ memory usage, and monitoring it alongside consumed memory can help you determine if virtual machines have sufficient memory allocated to them. If a VM’s active memory is consistently significantly below it’s consumed memory, it means it has more memory allocated to it than it needs and, as a consequence, the host has less memory available for other VMs than it could. To amend this, consider changing your VM’s configured size or memory reservation.
At the VM level, the mem.usage metric measures what percentage of its configured memory a VM is actively using Ideally, a VM should not always be using all of its configured memory. If it is consistently using a large portion of its configured memory, the VM will be less resilient to any spikes in memory usage if its ESXi host cannot allocate additional memory. If this is the case, consider reconfiguring VM memory size, updating its memory allocation settings (shares, reservations, etc.), or migrating the VM to a cluster with more memory.
At the host level, memory usage represents the percentage of an ESXi host’s physical memory that is being consumed. If memory usage at the host level is consistently high, it may not be able to provision memory to the VMs that need it and it will need to run memory ballooning more often or may even begin to start swapping memory.
i ahve shared snipt it ,Yellow highlited is consumed memory which is from hosst memory you assigned to VM and in Red colour its is showing active memory which is using by guest OS or real time memory usage .
VM-Utilized Memory: VM-utilized memory refers to the amount of physical memory (RAM) that is actively being used by a virtual machine (VM). It includes the memory allocated to the VM's operating system, applications, and other processes that are actively running inside the VM. This metric shows the actual memory usage by the VM at a given point in time.
Consumed Memory: Consumed memory, on the other hand, represents the total amount of host physical memory that is reserved for a VM, regardless of whether it is actively used or not. It includes both the actively utilized memory (as in VM-utilized memory) and the memory that is allocated to the VM but not currently being utilized. Consumed memory takes into account the memory overhead of the VM, such as memory reserved for virtualization management, device drivers, and other system-level components.
In summary, VM-utilized memory shows the actual memory usage within a VM, while consumed memory reflects the total physical memory allocated to the VM, including both actively used and reserved but unused memory. The consumed memory metric is often used for capacity planning and resource allocation purposes, as it represents the maximum amount of memory that a VM can consume.