VMware vSphere SDKs and Tools 6.7

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Introduction to Virtual Machine File Management

You can use the
or vCLI commands to access different types of storage devices that your
host discovers and to deploy datastores on those devices.
Datastores are logical containers, analogous to file systems, that hide specifics of each storage device and provide a uniform model for storing virtual machine files. Datastores can be used for storing ISO images, virtual machine templates, and floppy images. The
uses the term datastore exclusively. In vCLI, the term datastore, as well as VMFS or NFS volume, refer to the same logical container on the physical device.
Depending on the type of storage you use, datastores can be backed by the VMFS and NFS file system formats.
  • Virtual Machine File System (VMFS) - High-performance file system that is optimized for storing virtual machines. Your host can deploy a VMFS datastore on any SCSI-based local or networked storage device, including Fibre Channel and iSCSI SAN equipment. As an alternative to using the VMFS datastore, your virtual machine can have direct access to raw devices and use a mapping file (RDM) as a proxy.
    You manage VMFS and RDMs with the
    , or the
    vmkfstools
     command.
  • Network File System (NFS) - The NFS client built into
    uses the NFS protocol over TCP/IP to access a designated NFS volume that is located on a NAS server. The
    host can mount the volume and use it for its storage needs. vSphere supports versions 3 and 4.1 of the NFS protocol. Typically, the NFS volume or directory is created by a storage administrator and is exported form the NFS server. The NFS volumes do not need to be formatted with a local file system, such as VMFS. You can mount the volumes directly and use them to store and boot virtual machines in the same way that you use VMFS datastores. The host can access a designated NFS volume located on an NFS server, mount the volume, and use it for any storage needs.
    You manage NAS storage devices from the
    or with the
    esxcli storage nfs
     command. The diagram below illustrates different types of storage, but it is for conceptual purposes only. It is not a recommended configuration.
Virtual Machines Accessing Different Types of Storage
Displays relations between virtual machines and different types of storage. A group of virtual machines on a single host are connected to storages of type fibre array, iSCSI array, and NAS appliance. The virtual machines connected to iSCSI array and NAS appliance require TCP/IP connectivity. The fibre array and iSCSI array storages are connected to VMFS instances, while the NAS appliance is connected to an NFS instance. Both VMFS and NFS are connected to LAN nodes. The fibre array LAN node is connected to a fibre channel HBA. The firs iSCSI array LAN node is linked to an iSCSI hardware initiator and the second LAN node is connected to a software initiator through an ethernet NIC. The NAS appliance LAN node is connected to an ethernet NIC. An additional virtual machine is linked to VMFS on the host through local ethernet SCSI.

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