Here we can see, “Virtual Disk Storage and Networking”
In a virtual environment, computers aren’t the only objects that are virtualized. Virtualization produces not only virtual computers but also creates virtual disc storage. Disk virtualization allows you to pool disc storage from various physical disc storage devices and distribute it to your virtual machines as needed.
Disk storage virtualization isn’t a new concept. In fact, in real-world storage infrastructure, there are numerous layers of virtualization. The physical disc drives are at the very bottom of the hierarchy. In most cases, physical disc drives are grouped in arrays of individual drives. Bundling is a sort of virtualization in which an image of a single big hard drive is created that isn’t present. Four 2TB disc drives, for example, might be stacked in an array to generate a single 8TB disc drive.
Disk arrays are typically used to provide data redundancy and data protection. RAID stands for Redundant Array of Inexpensive Disks, and it’s what this is known as.
RAID-10, for example, allows you to build mirrored pairs of disc drives in which data is always written to both drives in a mirror pair. As a result, if one of the drives in a mirror pair fails, the other can take over. The useable capacity of the entire array is equal to one-half of the total capacity of the drives in the array when using RAID-10. A RAID-10 array with four 2TB drives, for example, has two pairs of mirrored 2TB disc drives, resulting in a total usable capacity of 4TB.
Another frequent RAID configuration is RAID-5, which combines disc drives and uses one of the drives for redundancy. The remaining drives can then be utilized to recreate the data on the failed drive if one of the array’s drives fails. The sum of the capacities of the individual drives, minus one, is the total capacity of a RAID-5 array. A RAID-5 setup of four 2TB drives, for example, has a total usable capacity of 6TB.
The host computers in a typical virtual environment can be connected to disc storage in a variety of ways:
- Local disk storage: Disk drives are mounted directly into the host computer and connected to the host computer via its internal disc drive controllers in local disc storage. A host computer, for example, might have four 1TB disc drives placed in the same chassis as the computer. These four drives might be used to create a RAID-10 array with a 2TB useable capacity.
The main disadvantages of local disc storage are that it is restricted by the physical capacity of the host machines and that it is only accessible by the host computer in which it is installed.
- Storage Area Network (SAN): Disk drives are contained in a separate device connected to the host via a high-speed controller in a Storage Area Network (SAN). The SAN is different from local storage in that it is a distinct device. Its high-speed connection to the host is typically as fast as local disc storage’s internal connection, but the SAN contains a separate storage controller that manages the disc drives.
A typical SAN can house a dozen or more disc drives and connect to several hosts at fast speeds. A SAN’s capacity can often be increased by adding one or more expansion chassis, each of which can hold a dozen or more disc drives. As a result, a single storage area network (SAN) can manage hundreds of terabytes of disc data.
- Network Accessible Storage (NAS): It’s similar to a SAN except that instead of using a high-speed controller to connect to the hosts, a NAS uses regular Ethernet connections and TCP/IP. NAS is the cheapest of all disc storage options, but it’s also the slowest.
The hypervisor consolidates storage and produces virtual pools of disc storage called data stores, regardless of how the storage is connected to the host. A hypervisor with access to three 2TB RAID5 storage arrays, for example, may combine them to produce a single 6TB data store.
You can construct volumes from this data store, which are effectively virtual disc drives that can be assigned to a specific virtual machine. The operating system can then mount the virtual machine’s volumes to generate drives that the operating system can access when it is installed in the virtual machine.
Consider a virtual machine that runs Windows Server as an example. You might see a C:\drive with a capacity of 100GB if you connect to the virtual machine, log in, and use Windows Explorer to look at the disc storage that’s available to the system. The virtual machine’s C: disc is a 100GB volume created by the hypervisor and tied. The 100GB volume is then assigned from a data store that may be as large as 4TB. The data store is made up of disc storage in a SAN connected to the host, which could be a RAID-10 array made up of four 2TB physical disc drives.
As you can see, there are at least four layers of virtualization required to make raw storage available to the guest operating system on physical disc drives:
- RAID-10 is used to combine physical disc drives into a single disc image with built-in redundancy. In effect, RAID-10 is the initial virtualization layer, and the SAN is solely responsible for this layer.
- The hypervisor abstracts the storage accessible on the SAN to build data stores. This is effectively a second virtualization level.
- Volumes are created from portions of a data repository and then provided to virtual machines. Volumes represent virtualization’s third layerVirtualization’s.
- The guest operating system sees the volumes as physical devices that can be mounted and formatted to make usable disc storage available to the user. This is the fourth virtualization layer.
Although it may appear to be too difficult, these levels of virtualization allow you a lot of storage management options. New disc arrays or NAS can be added to a SAN, and new data stores can be formed without disturbing existing data stores. Volumes can be moved from one data store to another without causing any disruption to the virtual machines to which they are associated. In reality, you may change the size of a volume on the fly, and the virtual machine will immediately notice the increased storage capacity of its disc drives without having to reload.
In networking, what is a virtual disc?
In virtualization technologies, a virtual drive is a form of the logical drive. A virtual drive is similar to a physical disc that the hypervisor instals natively in a virtual machine or virtual server. A virtual disc drive is another name for a virtual drive.
What is a virtual disk’s purpose?
A virtual disc is a file (or a series of files) on the host system that appears to the guest operating system as a physical disc drive. Virtual hard disc files have a. vmdk extension and store information such as the operating system, software files, and data files.
What does the term “virtual storage” mean?
The pooling of physical storage from numerous network storage devices into what seems to be a single storage device administered from a central console is known as virtual storage. Commodity hardware or less expensive storage can be used to provide enterprise-class capabilities thanks to virtualization.
What are the various virtual disc types?
- Oracle VirtualBox uses a virtual disc image (VDI).
- VMware’s Virtual Machine Disk (VMDK) is a type of virtual machine disc.
- Microsoft and Citrix employ the Virtual Hard Disk (VHD).
- Microsoft’s Virtual Hard Disk (VHDX) technology.
What is the location of virtual discs?
VMware Workstation creates virtual hard drives, which are made up of files that would normally be saved on your host computer’s hard disc in the most common configurations.
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