To enhance performance, install ESXi on a robust system with more RAM than the minimum required and with multiple physical disks.

For ESXi system requirements, see ESXi Hardware Requirements. See also the technical papers on vSphere 5 performance at https://www.vmware.com/pdf/Perf_Best_Practices_vSphere5.5.pdf.

Recommendations for Enhanced Performance

System Element

Recommendation

RAM

ESXi hosts require more RAM than typical servers. Provide at least 8GB of RAM to take full advantage of ESXi features and run virtual machines in typical production environments. An ESXi host must have sufficient RAM to run concurrent virtual machines. The following examples are provided to help you calculate the RAM required by the virtual machines running on the ESXi host.

Operating four virtual machines with Red Hat Enterprise Linux or Windows XP requires at least 3GB of RAM for baseline performance. This figure includes approximately 1024MB for the virtual machines, 256MB minimum for each operating system as recommended by vendors.

Running these four virtual machines with 512MB RAM requires that the ESXi host have approximately 4GB RAM, which includes 2048MB for the virtual machines.

These calculations do not take into account possible memory savings from using variable overhead memory for each virtual machine. See vSphere Resource Management .

Dedicated Fast Ethernet adapters for virtual machines

Place the management network and virtual machine networks on different physical network cards. Dedicated Gigabit Ethernet cards for virtual machines, such as Intel PRO 1000 adapters, improve throughput to virtual machines with high network traffic.

Disk location

Place all data that your virtual machines use on physical disks allocated specifically to virtual machines. Performance is better when you do not place your virtual machines on the disk containing the ESXi boot image. Use physical disks that are large enough to hold disk images that all the virtual machines use.

VMFS5 partitioning

The ESXi installer creates the initial VMFS volumes on the first blank local disk found. To add disks or modify the original configuration, use the vSphere Web Client. This practice ensures that the starting sectors of partitions are 64K-aligned, which improves storage performance.

Note

For SAS-only environments, the installer might not format the disks. For some SAS disks, it is not possible to identify whether the disks are local or remote. After the installation, you can use the vSphere Web Client to set up VMFS.

Processors

Faster processors improve ESXi performance. For certain workloads, larger caches improve ESXi performance.

Hardware compatibility

Use devices in your server that are supported by ESXi 5.5 drivers. See the Hardware Compatibility Guide at http://www.vmware.com/resources/compatibility.