What is Storage Virtualization?

Storage virtualization is the pooling of actual physical storage from a number of storage gadgets into what appears to be a solitary storage device — or pool of available storage ability — that is managed from a central console. The technology relies on software package to recognize readily available storage potential from actual physical units and to then aggregate that capability as a pool of storage that can be applied by standard architecture servers or in a digital atmosphere by virtual machines (VMs).

The digital storage software intercepts enter/output (I/O) requests from actual physical or digital devices and sends these requests to the ideal actual physical site of the storage products that are aspect of the over-all pool of storage in the virtualized environment. To the consumer, the several storage resources that make up the pool are unseen, so the digital storage seems like a single bodily drive, share or sensible unit variety (LUN) that can take standard reads and writes.

A pretty basic kind of storage virtualization is represented by a computer software virtualization layer concerning the hardware of a storage source and a host — a private laptop or computer (Personal computer), a server or any gadget accessing the storage — that helps make it probable for running methods (OSes) and purposes to accessibility and use the storage. Even a RAID array can sometimes be regarded as a type of storage virtualization. A number of physical drives in the array are presented to the consumer as a single storage machine that, in the background, stripes and replicates info to multiple disks to increase I/O overall performance and to guard knowledge in circumstance a single push fails.


Kinds of storage virtualization: Block vs. file

There are two primary strategies of virtualizing storage: file-dependent or block-based. File-primarily based storage virtualization is a unique use case, applied to community-connected storage (NAS) systems. Using the Server Message Block (SMB) or Prevalent Online File Process (CIFS) in Home windows server environments, or Network File System (NFS) protocols for Linux programs, file-centered storage virtualization breaks the dependency in a ordinary NAS array concerning the knowledge remaining accessed and the place of bodily memory. The pooling of NAS sources can make it less complicated to cope with file migrations in the qualifications, which will help make improvements to overall performance. Generally, NAS techniques are not that complex to deal with, but storage virtualization drastically simplifies the task of running various NAS devices by way of a one administration console.

Block-based or block entry storage — storage sources typically accessed through a Fibre Channel (FC) or Net Small Pc Procedure Interface (iSCSI) storage space network (SAN) — is much more routinely virtualized than file-primarily based storage devices. Block-dependent units summary the reasonable storage, this kind of as a push partition, from the real physical memory blocks in a storage device, such as a really hard disk push (HDD) or strong-state memory gadget. Because it operates in a comparable vogue to the native travel application, you can find significantly less overhead for go through and create processes, so block storage techniques will conduct much better than file-primarily based techniques.

The block-based mostly operation permits the virtualization management software package to obtain the ability of the readily available blocks of storage house throughout all virtualized arrays and pool them into a shared source to be assigned to any selection of VMs, bare-steel servers or containers. Storage virtualization is particularly effective for block storage. Unlike NAS techniques, taking care of SANs can be a time-consuming process consolidating a variety of block storage devices less than a solitary administration interface that usually shields end users from the cumbersome techniques of LUN configuration, for example, can be a considerable timesaver.

Four types of storage virtualization
Virtualization methods can be utilized to block, disk, tape and file storage.

An early version of block-centered virtualization was IBM’s SAN Volume Controller (SVC), now named IBM Spectrum Virtualize. The application operates on an appliance or storage array and results in a solitary pool of storage by virtualizing LUNs connected to servers linked to storage controllers. Spectrum Virtualize also permits customers to tier block info to community cloud storage.

A different early storage virtualization products was Hitachi Knowledge Systems’ TagmaStore Common Storage Platform, now recognized as Hitachi Virtual Storage Platform (VSP). Hitachi’s array-dependent storage virtualization enabled shoppers to develop a one pool of storage across independent arrays, even those people from other foremost storage suppliers.

How storage virtualization will work

To deliver entry to the data stored on the physical storage units, the virtualization software program needs to both produce a map applying metadata or, in some scenarios, use an algorithm to dynamically locate the data on the fly. The virtualization software program then intercepts examine and produce requests from apps and making use of the map it has designed it can obtain or conserve the knowledge to the ideal actual physical device. This course of action is equivalent to the system utilised by Personal computer working programs when retrieving or saving application information.

Storage virtualization disguises the true complexity of a storage method, these as a SAN, which will help a storage administrator carry out the tasks of backup, archiving and recovery extra effortlessly and in significantly less time.

In-band vs. out-of-band virtualization

There are generally two styles of virtualization that can be utilized to a storage infrastructure: in-band and out-of-band.

  • In-band virtualization — also termed symmetric virtualization — handles the details that’s being study or saved and the handle information and facts (e.g., I/O directions, metadata) in the very same channel or layer. This setup permits the storage virtualization to supply additional innovative operational and administration functions this kind of as details caching and replication expert services.
  • Out-of-band virtualization — or uneven virtualization — splits the information and control paths. Due to the fact the virtualization facility only sees the control guidance, highly developed storage characteristics are ordinarily unavailable.

Virtualization methods

Storage virtualization right now ordinarily refers to ability that is accrued from multiple physical gadgets and then made out there to be reallocated in a virtualized natural environment. Modern-day IT methodologies, this sort of as hyper-converged infrastructure (HCI) and containerization, just take benefit of digital storage, in addition to virtual compute energy and generally virtual network capability.

While waning as a backup goal media, tape storage is still broadly employed for archiving infrequently accessed information. Archival info tends to be voluminous storage virtualization can be utilized for tape media to make it a lot easier to manage substantial information outlets. Linear tape file system (LTFS) is a kind of tape virtualization that would make a tape seem like a regular NAS file storage machine and tends to make it substantially a lot easier to uncover and restore data from tape using a file-level directory of the tape’s contents.

There are several techniques storage can be used to a virtualized setting:

Host-based storage virtualization is software-based mostly and most generally found in HCI programs and cloud storage. In this type of virtualization, the host, or a hyper-converged procedure created up of various hosts, provides virtual drives of various potential to the visitor equipment, whether they are VMs in an business setting, bodily servers or PCs accessing file shares or cloud storage. All of the virtualization and administration are performed at the host amount by way of software package, and the physical storage can be pretty much any device or array. Some server OSes have virtualization abilities designed in these kinds of as Windows Server Storage Spaces.

Array-primarily based storage virtualization most generally refers to the method in which a storage array acts as the most important storage controller and runs virtualization software program, enabling it to pool the storage sources of other arrays and to current distinctive types of physical storage for use as storage tiers. A storage tier may perhaps comprise reliable-point out drives (SSDs) or HDDs on the different virtualized storage arrays the bodily area and precise array is concealed from the servers or buyers accessing the storage.

Network-centered storage virtualization is the most popular sort made use of in enterprises now. A community system, these types of as a clever change or function-built server, connects to all storage gadgets in an FC or iSCSI SAN and offers the storage in the storage community as a single, digital pool.

Positive aspects and makes use of of storage virtualization

When to start with launched extra than two a long time back, storage virtualization tended to be tricky to put into practice and experienced confined applicability insofar as which helps make and versions of storage arrays the readily available engineering would perform with. For the reason that it was initially host-based, storage virtualization program had to be put in and maintained on all servers needing entry to the pooled storage methods. As it matured, the technological know-how could be executed in a range of techniques (as described over), which produced it easier to deploy in a range of environments, as people could select the virtualization approach that produced the most sense for their shops’ existing infrastructure.

Even further growth of virtualization software program, along with standards these as Storage Administration Initiative Specification (SMI-S), permitted virtualization products to work with a wider variety of storage techniques, building it a substantially much more desirable choice for enterprises having difficulties with spiraling storage capacities.

Some of the gains and utilizes of storage virtualization include:

  • Less complicated management. A single administration console to watch and retain several virtualized storage arrays cuts down on the time and effort and hard work important to deal with the physical techniques. This is particularly valuable when storage programs from a number of vendors are in the virtualization pool.
  • Improved storage utilization. Pooling storage capability throughout multiple units helps make it less difficult to allocate so the ability is a lot more proficiently allotted and employed. With unconnected, disparate programs, it truly is most likely some methods will conclude up running at or in the vicinity of ability, whilst many others are barely applied.
  • Extend the existence of more mature storage units. Virtualization delivers a good way to prolong the usefulness of older storage gear by which include them in the pool as a tier to deal with archival or significantly less significant info.
  • Add highly developed options universally. Some much more highly developed storage characteristics like tiering, caching and replication can be executed at the virtualization stage. This can help standardize these procedures throughout all member units and can provide these highly developed capabilities to devices that may well be lacking them.