Disk Types 磁盘类型

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Disk Types: Virtual and Physical
In the most common configurations, vmware Workstation creates virtual hard disks, which are made up of files that are typically stored on your host computer's hard disk. In some circumstances, you may need to give your virtual machine direct access to a physical hard drive on your host computer.
1. Virtual Disk
A virtual disk is a file or set of files that appears as a physical disk drive to a guest operating system. The files can be on the host machine or on a remote computer. When you configure a virtual machine with a virtual disk, you can install a new operating system onto the virtual disk without repartitioning a physical disk or rebooting the host.
Virtual disks can be as large as 950GB (IDE or SCSI). Depending on the size of the virtual disk and the host operating system, VMware Workstation creates one or more files to hold each virtual disk.
By default, the actual files used by the virtual disk start out small and grow to their maximum size as needed. The main advantage of this approach is the smaller file size. Smaller files require less storage space and are easier to move if you want to move the virtual machine to a new location. However, it takes longer to write data to a disk configured in this way.
You may also configure virtual disks so all the disk space is allocated at the time the virtual disk is created. This approach provides enhanced performance and is useful if you are running performance-sensitive applications in the virtual machine.
Virtual disks can be set up as IDE disks for any guest operating system. They can be set up as SCSI disks for any guest operating system that has a driver for the LSI Logic or BusLogic SCSI adapter available in a VMware Workstation virtual machine. You determine which SCSI adapter to use at the time you create the virtual machine.
Note: To use SCSI disks in a Windows XP virtual machine, you need a special SCSI driver available from the download section of the VMware Web site at www.vmware.com/download. Follow the instructions on the Web site to use the driver with a fresh installation of Windows XP.
A virtual disk of either type can be stored on either type of physical hard disk. That is, the files that make up an IDE virtual disk can be stored on either an IDE hard disk or a SCSI hard disk. So can the files that make up a SCSI virtual disk. They can also be stored on other types of fast-access storage media, such as DVD or CD-ROM discs.
A key advantage of virtual disks is their portability. Because the virtual disks are stored as files on the host machine or a remote computer, you can move them easily to a new location on the same computer or to a different computer. You can also use VMware Workstation on a Windows host to create virtual disks, then move them to a Linux computer and use them under VMware Workstation for Linux - or vice versa. For information about moving virtual disks, see Moving and Sharing Virtual Machines.

磁盘的类型：虚拟磁盘和物理磁盘
通常情况下，Vm创建虚拟磁盘，虚拟磁盘通常由宿主机磁盘上的几个文件组成。在某些情况下你可能需要让客户机访问宿主机上的物理磁盘。VM创建一个或多个文件来保存虚拟磁盘
1．虚拟磁盘。
虚拟磁盘是物理磁盘上的一个或一组文件，这些文件可以位于宿主机硬盘或远程计算机上。当配置了一个有虚拟磁盘的虚拟机时，你可以不用在真实的硬盘上重新分区和重起主机，完全可以在虚拟机中安装新的操作系统。
虚拟磁盘最大支持950GB(IDE或SCSI)，依赖与物理磁盘的大小。
默认情况下，虚拟磁盘文件是根据需要由小逐渐增大的，这种方法的优点就是能最大限度的控制虚拟磁盘文件的大小。较小的文件需要较小的空间并且可以在有需要的情况下方便移动虚拟机文件。然而这种方式读写磁盘的效率低下。另一种方式是在创建虚拟磁盘的时候就分配好所占用的磁盘空间
虚拟磁盘可以为任意客户机设置为IDE磁盘，也可以为带有LSI Logic 和 BusLogic SCSI卡的客户机设置为SCSI磁盘，创建虚拟机的时候可以选择SCSI卡。
注意：在Windows XP professinoal 虚拟机上使用SCSI磁盘需要到Vmware的官方网站上下载一个专用的SCSI驱动程序 www.vmware.com/download，在最初安装Windows XP的时候需要加载该驱动程序。