VMWare ESX 4.1 - Guest memory usage

[Former Member]

Hi,

We are running an ESX Server 4.1 with 36 GB RAM. We have installed 4 VM (Windows Server 2008 R2 and MS SQL Server 2008 R2), each defined with 8 GB RAM (1 ERP 6.0 EHP3 ABAPJAVA, 1 ERP 6.0 EHP4 ABAPJAVA, 1 Enterprise Portal 7.02 and 1 Solution Manager 7.0 EHP1). Each SAP system is up and running, performances are good, but only a few users are working on each of them. I see a warning in Vcenter concerning the RAM usage (94%), but the guest memory usage is low (from 5 to 12% in average during the last month).

How can I optimize ?

Kind regards,

Christophe

[Former Member]

Hi Christophe,

first of all, the warning you see is not critical. It is just a standard warning that comes up when a standard theshold of memory usage is reached. The 4 GB RAM you have left on the host should be sufficient to cover the memory allocation overheads of the VMs and the memory that is needed by the ESX hypervisor.

I assume you reserved 100 % of the assigned memory (mandatory for SAP virtualization). Reserved memory cannot be used by other VMs, therefore it is "not assignable" from the perspective of the hypervisor. This could be the reason why the threshold of the warning is reached although the utilization inside the guest ("active" memory) is low.

Kind regards,

Matthias