Installation guide

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VMware ESX Server Administration Guide
Recommended Configuration Options
This section details options that can influence the performance of your virtual
machines. These settings are not required to run VMware ESX Server correctly.
SleepWhenIdle
The configuration file option monitor.SleepWhenIdle determines whether the
VMkernel deschedules an idle virtual machine. By default, this option is enabled, a
setting that ensures much better performance when running multiple virtual
machines.
When you are running only a single virtual machine (such as for benchmarking
VMware ESX Server), add the monitor.SleepWhenIdle option to the virtual
machine’s configuration file if you want to achieve the best possible performance in
the virtual machine (at the expense of responsiveness in the service console).
Create an option called monitor.SleepWhenIdle and set the value of this
option to 0, as described in Modifying the Configuration File Directly (Advanced Users
Only) on page 141.
Optimizing Disk Access Failure Modes
ESX Server includes configuration options that allow you to optimize how virtual
machines handle disk access failures. In particular, the
scsi<n>.returnBusyOnNoConnectStatus option determines how ESX
Server reports a failure to connect with a virtual SCSI adapter or failure to access it
after initiating a connection. By setting the option to TRUE or FALSE, you can
determine how the failure to access to a physical disk is represented to your virtual
machine.
• If the option is set to TRUE, ESX Server returns the error message SCSI BUSY.
• If the option is set to FALSE, the value ESX Server returns depends on the type
of SCSI controller you chose for that particular virtual device:
• If you chose the BusLogic adapter (i.e., if Virtual Device is set to
vmxbuslogic), your Virtual Machine receives the error message
DEVICE_NOT_THERE.
• If you chose the LSI Logic adapter (i.e., if Virtual Device is set to
vmxlsilogic), your Virtual Machine receives the error message
BTSTAT_SELTIME0.
You may need to set returnBusyOnNoConnectStatus to FALSE when disk
management software operating in a virtual machine needs to detect access failures.
For example, some types of disk mirroring software will not select a duplicate disk