VMware GSX Server 3 Administration, Administration Manual

Page: 196 / 240

www.vmware.com
196
VMware GSX Server Administration Guide
If you set this value too high, the host may thrash when other applications are run on
the host. If you set this value too low, virtual machines may perform poorly and you
cannot run as many virtual machines at once.
Using Additional Memory
By default, GSX Server limits the number of virtual machines that can run at once
based on the amount of memory specified in the Host Settings dialog box. This limit
prevents virtual machines from causing each other to perform poorly. If you try to
power on a virtual machine and there is not enough memory available, a warning
appears and the virtual machine fails to power on.
To increase the number or memory size of virtual machines that can run, adjust the
amount of virtual machine memory that the host operating system may swap to disk.
To change this setting, choose
Host > Settings > Memory and choose an option
under Additional memory .
Select one of the following options:
• Fit all virtual machine memory into reserved host RAM — Strictly apply the
reserved memory limit set in the top of the dialog box. This setting imposes the
tightest restrictions on the number and memory size of virtual machines that
may run at a given time. Because the virtual machines are running entirely in
RAM, they have the best possible performance.
• Allow some virtual machine memory to be swapped — Allow the host
operating system to swap a moderate amount of virtual machine memory to
disk if necessary. This setting allows you to increase the number or memory size
of virtual machines that can run on the host computer at a given time. It may
also result in reduced performance if virtual machine memory must be shifted
between RAM and disk.