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→Memory Swapping Configuration
In an ideal world, computers would have enough physical memory to run as many applications concurrently as any user could ever need. Unfortunately, that day has yet to come and most computer systems quickly use up all the available memory. In this scenario, the operating system performs a task called ''swapping'' whereby data held in memory is written to a hard disk to make room for other data. When the data written to the swap space on the disk is needed, the operating system writes some other memory based data to the disk to make room, and then reads previously swapped data back into memory. Whilst this seems like an elegant solution to the problem of limited memory availability, it has the downside that disk drives work much more slowly than random access memory (RAM). the more an operating system has to swap memory, the slower it will run.
As the use of memory and swap space has a significant impact on the performance of both the host system and virtual machines, VMware Server provides a number of configuration options in this area. To change host memory swapping settings, log into VI Web Access as a user with administrative privileges, select the host from the ''Inventory'' panel and click on ''Edit Host Settings'' in the ''Commands'' panel. The relevant settings are listed in the ''Additional Memory'' section of the dialog as illustrated in the following panel:
[[Image:vmware_server_2_host_swap_settings.jpg|Configurating VMware Server Host Swap Settings]]
The advanced memory settings provide three options each of which are described in the following table:
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<p>Memory Option</p>
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<p>Description</p>
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<td>
Fit all virtual machine memory into reserved host RAM
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<td>
Restricts virtual machines to running in memory only. Virtual machines are not swapped to disk thereby providing maximum performance. Host system must have sufficient memory for host operating system, all virtual machines and other host based applications.
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<td>Allow some virtual machine memory to be swapped</td>
<td>Allows some, but not all, of the memory used by virtual machines to be swapped to disk by the host operating system. Results in some performace degradation as compared to running solely in memory, but allows a greater number of virtual machines to be ruin concurrently.</td>
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<td>
Allow most virtual machine memory to be swapped
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<td>
Allows a larger amount of memory used by virtual machines to be swapped to disk. Allows the greatest number of virtual machines to run concurrently, but at the greatest risk of decreased overall performance due to potentially excessive swapping operations.
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== Host-wide Virtual Machine Startup and Shutdown ==
