memory resources

[fer82]

Hello everybody,

I've a question about the memory resources in my environment.

I have a cluster with

4 ESX 4.1 x 32766 MB

1 ESX 4.1 x 20470 MB.

So I have 151534 MB of RAM.

I can see that in cluster summary tab.

Now, in Resource Allocation tab I only see

Total capacity           134648 MB

Reserved capacity     11955 MB

Available capacity      122693 MB

I haven't got any reservation in any vm.

I understand the "Reserved Capacity" includes the "system" reservation (398 MB in each esx), the "service console" reservation (500MB each esx), and all the reservations of "system resource pools". Isn't it?

I undestand too that for each vm i have, there are an overhead. But I don't know if this is reflected on the "reserved capacity" field, or where is it!?

But I don't understand where is the remaining of memory:

the gap between all physical memory: 151534

and the "total capacity": 134648

      151534-134648 = 16886 MB are lost in...¿?

In addition, if I have 151534 "real" MB, and only could be available 122693, there's a ¡¡¡19% of memory lost in the Vsphere's management!!!

ARE THAT NUMBERS OK?

Thank you very much for your answers and comments (and so sorry for my language faults!).

*fer*

[weinstein5]

It is also not including the memory used by the hyperviro the vmkernel - the operating system of your ESX host -

[fer82]

Hello,

Nobody knows how it works?

How about your % of memory lost in vsphere management?

Thank you!

[shishir08]

Every virtual machine running on an ESX host consumes some memory  overhead additional to the current usage of its configured memory. This  extra space is needed by ESX for the internal VMkernel datastructures  like virtual machine frame buffer  and mapping table for memory  translation (mapping physical virtual machine memory to machine memory).

Once the virtual machine has started up, the virtual machine monitor  (VMM) can request additional memory space. The VMM will request the  space, but the VMkernel is not required to supply it. If the VMM does  not obtain the extra memory space, the virtual machine will continue to  function but this can lead to performance degradation. The VMkernel  treats virtual machine overhead reservation the same as VM-level memory reservation and it will not reclaim this memory once it used.

VMkernel will not allow the virtual machine to be powered up if  reservations cannot be guaranteed, this means that the effective memory  reservation for a virtual machine is the user configured memory  reservation (VM-level reservation) plus the overhead reservation.

This means that during the design phase of a resource pool, the memory  overhead of a virtual machine must be included in the calculation of the  memory reservation specified on the resource pool.

HTH