Which Storage Technology Can Be Extended to Span Several Physical Storage Extents

The VMwarevSphere storage architecture consists of layers of brainchild that hide the differences and manage the complexity amongst physical storage subsystems.

To the applications and guest operating systems inside each virtual automobile, the storage subsystem appears as a virtual SCSI controller connected to ane or more virtual SCSI disks. These controllers are the simply types of SCSI controllers that a virtual auto can run into and admission. These controllers include BusLogic Parallel, LSI Logic Parallel, LSI Logic SAS, and VMware Paravirtual.

The virtual SCSI disks are provisioned from datastore elements in the datacenter. A datastore is like a storage appliance that delivers storage infinite for virtual machines across multiple physical hosts. Multiple datastores can be aggregated into a single logical, load-balanced pool chosen a datastore cluster.

The datastore brainchild is a model that assigns storage space to virtual machines while insulating the invitee from the complication of the underlying physical storage engineering. The invitee virtual machine is non exposed to Fibre Aqueduct SAN, iSCSI SAN, direct attached storage, and NAS.

Each datastore is a physical VMFS volume on a storage device. NAS datastores are an NFS volume with VMFS characteristics. Datastores tin bridge multiple physical storage subsystems. A single VMFS book tin can contain 1 or more LUNs from a local SCSI deejay array on a physical host, a Fibre Channel SAN disk farm, or iSCSI SAN deejay farm. New LUNs added to whatever of the concrete storage subsystems are detected and made available to all existing or new datastores. Storage capacity on a previously created datastore tin can be extended without powering down physical hosts or storage subsystems. If whatsoever of the LUNs within a VMFS volume fails or becomes unavailable, simply virtual machines that utilise that LUN are affected. An exception is the LUN that has the starting time extent of the spanned volume. All other virtual machines with virtual disks residing in other LUNs proceed to function as normal.

Each virtual machine is stored equally a set of files in a directory in the datastore. The deejay storage associated with each virtual guest is a prepare of files within the guest's directory. You can operate on the invitee deejay storage as an ordinary file. The disk storage can be copied, moved, or backed upwardly. New virtual disks tin be added to a virtual machine without powering it down. In that instance, a virtual disk file  (.vmdk) is created in VMFS to provide new storage for the added virtual disk or an existing virtual disk file is associated with a virtual automobile.

VMFS is a clustered file arrangement that leverages shared storage to permit multiple concrete hosts to read and write to the same storage simultaneously. VMFS provides on-disk locking to ensure that the same virtual car is not powered on past multiple servers at the same time. If a physical host fails, the on-disk lock for each virtual machine is released then that virtual machines can be restarted on other physical hosts.

VMFS also features failure consistency and recovery mechanisms, such equally distributed journaling, a failure-consistent virtual machine I/O path, and virtual machine state snapshots. These mechanisms tin assist quick identification of the cause and recovery from virtual machine, physical host, and storage subsystem failures.

VMFS as well supports raw device mapping (RDM). RDM provides a mechanism for a virtual machine to take direct access to a LUN on the physical storage subsystem (Fibre Aqueduct or iSCSI only). RDM supports two typical types of applications:

■	SAN snapshot or other layered applications that run in the virtual machines. RDM meliorate enables scalable backup offloading systems using features inherent to the SAN.
■	Microsoft Clustering Services (MSCS) spanning physical hosts and using virtual-to-virtual clusters as well equally concrete-to-virtual clusters. Cluster information and quorum disks must be configured as RDMs rather than files on a shared VMFS.

Supported Storage Adapters:

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Storage adapters provide connectivity for your ESXi host to a specific storage unit or network.

ESXi supports different classes of adapters, including SCSI, iSCSI, RAID, Fibre Channel, Fibre Channel over Ethernet (FCoE), and Ethernet. ESXi accesses the adapters directly through device drivers in the VMkernel.

View Storage Adapters Data:

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Use the vSphere Customer to display storage adapters that your host uses and to review their data.

Procedure

one: In Inventory, selectHosts and Clusters.

2: Select a host and click theConfiguration tab.

3: In Hardware, selectStorage Adapters.

4:To view details for a specific adapter, select the adapter from the Storage Adapters list.

5: To listing all storage devices the adapter can access, clickDevices.

6: To list all paths the adapter uses, clickPaths

Types of Physical Storage:

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The ESXi storage direction procedure starts with storage space that your storage administrator preallocates on different storage systems.

ESXi supports the post-obit types of storage:

Local Storage : Stores virtual machine files on internal or straight connected external storage disks.

Networked Storage: Stores virtual auto files on external storage disks or arrays attached to your host through a direct connexion or through a high-speed network.

Local Storage:

Local storage can be internal hard disks located inside your ESXi host, or it can be external storage systems located outside and continued to the host direct through protocols such as SAS or SATA.

Local storage does not require a storage network to communicate with your host. You need a cable connected to the storage unit and, when required, a compatible HBA in your host.

ESXi supports a variety of internal or external local storage devices, including SCSI, IDE, SATA, USB, and SAS storage systems. Regardless of the blazon of storage you lot use, your host hides a concrete storage layer from virtual machines.

Networked Storage:

Networked storage consists of external storage systems that your ESXi host uses to shop virtual machine files remotely. Typically, the host accesses these systems over a loftier-speed storage network.

Networked storage devices are shared. Datastores on networked storage devices can be accessed past multiple hosts concurrently. ESXi supports the following networked storage technologies.

Note

Accessing the same storage through different transport protocols, such equally iSCSI and Fibre Aqueduct, at the aforementioned time is not supported.

Fibre Channel (FC):

Stores virtual machine files remotely on an FC storage area network (SAN). FC SAN is a specialized high-speed network that connects your hosts to high-functioning storage devices. The network uses Fibre Channel protocol to transport SCSI traffic from virtual machines to the FC SAN devices.

Fibre Channel Storage

In this configuration, a host connects to a SAN textile, which consists of Fibre Aqueduct switches and storage arrays, using a Fibre Channel adapter. LUNs from a storage assortment go bachelor to the host. You lot tin can admission the LUNs and create datastores for your storage needs. The datastores employ the VMFS format.

Internet SCSI (iSCSI):

Stores virtual machine files on remote iSCSI storage devices. iSCSI packages SCSI storage traffic into the TCP/IP protocol and so that it can travel through standard TCP/IP networks instead of the specialized FC network. With an iSCSI connection, your host serves as the initiator that communicates with a target, located in remote iSCSI storage systems.

ESXi offers the following types of iSCSI connections:

Hardware iSCSI: Your host connects to storage through a third-party adapter capable of offloading the iSCSI and network processing. Hardware adapters tin can exist dependent and contained.

Software iSCSI :Your host uses a software-based iSCSI initiator in the VMkernel to connect to storage. With this type of iSCSI connection, your host needs only a standard network adapter for network connectivity.

Yous must configure iSCSI initiators for the host to access and display iSCSI storage devices.

iSCSI Storage depicts different types of iSCSI initiators.

iSCSI Storage

In the left example, the host uses the hardware iSCSI adapter to connect to the iSCSI storage system.

In the right example, the host uses a software iSCSI adapter and an Ethernet NIC to connect to the iSCSI storage.

iSCSI storage devices from the storage system become bachelor to the host. Y'all can admission the storage devices and create VMFS datastores for your storage needs.

Network-attached Storage (NAS)

Stores virtual motorcar files on remote file servers accessed over a standard TCP/IP network. The NFS client congenital into ESXi uses Network File System (NFS) protocol version 3 to communicate with the NAS/NFS servers. For network connectivity, the host requires a standard network adapter.

NFS Storage

Shared Serial Attached SCSI (SAS)

Stores virtual machines on direct-attached SAS storage systems that offering shared admission to multiple hosts. This type of admission permits multiple hosts to access the aforementioned VMFS datastore on a LUN

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Source: https://cloudmaster.co.in/storage-connectivity-to-vsphere/

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