Networking: A Beginner’s Guide Fifth Edition- P80:I have run into many people over the years who have gained good even impressive working knowledge of PCs, operating systems, applications, and common problems and solutions. Many of these people are wizards with desktop computers. | Chapter 23 Introduction to Virtualization 377 Figure 23-8. Setting virtual hard disk properties File options If you select the checkbox Allocate All Disk Space Now VMware will create a virtual hard disk file that is the size you selected. Otherwise VMware will automatically expand the virtual hard disk file s size as the space is used. The trade-off is that if you choose to allocate the space immediately the virtual hard disk may consume much more space on the host system s hard disk than it is actually using. On the other hand if the space is allocated immediately then the performance of creating files or writing new blocks to the disk will be much faster because the space is already allocated. I recommend leaving this checkbox unchecked but choosing a size that is comfortably larger than you think you need. This way you efficiently use actual hard disk space and the automatic expansion process is generally not a huge price to pay for most uses. Independent disk mode This option allows you to configure a virtual hard disk as independent of any snapshots you make of the virtual machine. Note that you can have multiple virtual hard disks in each virtual machine and for some applications you may want the one or more of the virtual hard disks to not be part of the VMware snapshot process. Generally you will leave this option unselected. 378 Networking A Beginner s Guide Virtual device node This setting lets you choose whether VMware will emulate a SCSI or IDE controller for the virtual hard disk you are creating and which virtualized controller interface number will be used. Realize that the type of hard disk interface used on the host computer does not matter here VMware can run a virtual SCSI hard disk on a host computer that has only IDE drives or vice versa. For this setting VMware will propose a virtual disk interface type based on the guest operating system you chose and you should generally accept the default choice. Write caching You can set the virtual hard .
