Specifications

Table 2‑1. 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.
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16 VMware, Inc.