Server Configuration Recommendations; Basic Network Configurations - Intel S5520HC Installation Manual

VMware vSphere* 4.1 Installation Guide for ESX/ESXi* 4.1

Server Configuration Recommendations

Recommended for enhanced performance:
RAM: ESX* 4.1 hosts require more RAM than typical servers. An ESX* 4.1 host must be equipped with

sufficient RAM to run concurrent virtual machines. For example, running four virtual machines with 512
MB RAM requires that the ESX 4.1 host be equipped with approximately 4 GB RAM, which includes
2,048 MB for the virtual machines. Typical server deployments require at least 2-4 GB of memory per
virtual machine. This depends on the application needs for each server. These calculations do not take
into account possible memory savings from using variable overhead memory for each virtual machine.
See links in the appendix of the VMware Resource Management Guide for more information.
BIOS Settings: For Intel® Xeon® Processor systems, the processors must include support for Intel® VT.

Consult individual BIOS settings to ensure that Intel® VT is enabled. Many servers that include CPUs with
Intel® VT support might ship with Intel® VT disabled by default, so it must be enabled. Also enable
"Execute Disable Bit" in the BIOS to allow vSphere* to run. Please check both settings before installing
vSphere ESX* 4.1.
Processor Selection: When creating virtual machines it is recommended each virtual machine be

assigned a single virtual CPU or core. Multiple cores may be needed if an application requires more
performance or if running multi-threaded applications. However, there is overhead associated with
setting up to run with multiple vCPUs per VM. Performance is impacted when a virtual machine has to
wait until the cores are available. There is also more memory overhead required with multiple vCPUs.
Given these considerations, a single virtual CPU or core may be used and assigned to each VM. The
quantity of VMs running on each server depends on the CPU, disk I/O or networking loads for the
applications. Take into account the application workloads to determine not only the number of virtual
CPUs needed but also the networking and disk I/O requirements.
 Hard Disk Sizing: The size of the hard disks for virtual machines depends on loading requirements and
the disk sizes required by the application. For the vSphere ESX* 4.1 installation, allocate at least 50 GB
of storage space. In the installation setup instructions for this recipe, 50 GB of storage space is setup.
Calculate or determine if the virtual machines running on a LUN are sufficient to meet the demands for
the applications. In addition, reduce the number of VMs residing on a single LUN or virtual disk to avoid
SCSI reservation issues. SCSI reservations are made by the host when changes are made to the VMFS
metadata. When a host holds a reservation, the other hosts will report a SCSI reservation conflict when
I/O is requested from the LUN.
For more BIOS, CPU, memory and hard disk recommendations refer to the Performance Best Practices for
VMware vSphere® 4.1 available online at:
http://www.VMware.com/pdf/Perf_Best_Practices_vSphere4.1.pdf

Basic Network Configurations

For VMware* vSphere ESX* 4.1, adding the additional network cards provides extra bandwidth and
redundancy for service console and virtual machine network ports. It is recommended to use static IP
addresses for the ESX servers.
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