What is Storage Virtualization?

Virtualization is a very big term in Information Technology (IT) world and almost everything in this IT world has been virtualized. Whether it is a server, SAN, memory, network or storage, all things can be virtualized. In this article we will tell you about “Storage virtualization” with examples. Every system administrator or beginner should know about storage virtualization, so do read the full article.

 

Storage Virtualization Explained

 

What is Storage Virtualization?

 

Something which is not physical is a virtual object, which we cannot touch physically, but only have to believe it is present in some logical boundaries.

 

So, in simple terms Storage virtualization is the process of representing physical storage in the logical form to any server.

 

This logical storage will look like physical storage to a server or host, which means server won’t be able to differentiate between physical storage and logical storage. In storage virtualization, multiple physical disks are combined into a group and from that group of physical disks, virtual storage or logical storage blocks are assigned to a server for use.

The simplest examples of storage virtualization object are LUN’s (Logical unit number), Logical volume (LV), RAID groups, etc.

 

Benefits of Storage Virtualization

 

Below are some of the main advantages of storage virtualization.

  • It is highly scalable.
  • It allows easy addition and deletion of storage without affecting any application.
  • Easy data migration.
  • Easy storage management.

 

Diagram of Storage Virtualization

 

Diagram of Storage Virtualization

 

We have made a simple to understand diagram of storage virtualization. There are 2 servers with the virtual volumes. These virtual volumes may be mapped to different applications.

Between the actual storage and the virtual volume there is virtualization layer which helps in redirecting the I/O.

Understand that the physical storage or hard disks are combined or grouped together and then with the help of virtualization software this physical disks are divided into small blocks of data as per the requirements, which is presented to remote servers as a virtual disk. These virtual blocks of data look as the physical disk to the server.

Then this disk can be used to extend the filesystem or to create a new one.

 

Configurations of Storage Virtualization

 

Now the question is that how we do storage virtualization?

There are 2 ways in which storage virtualization can be implemented at the network. The first one is in-band method in which the virtualized environment configuration is stored in the data path.

The second method is out-of-band method, in which the virtualization implementation takes place external to the data path.

We are not going to cover these two methods in detail in this article as they are topics which needs to be discussed in details.

 

Types of Storage Virtualization

 

This is the important topic to know if we talk about storage virtualization. There are majorly two types of storage virtualization, which are:

1. Block level storage virtualization

2. File level storage virtualization

 

Block level storage virtualization is implemented in “SAN (storage area network)” and it provides a translation layer in the SAN, between the hosts and the storage arrays.

In this type of storage virtualization, servers are redirected to virtualized LUNs instead of LUN’s on the individual storage array. These virtualized LUNs are on the virtualized device.

File level storage virtualization happens at NAS (network attached storage) level and help in solving NAS problems by removing the dependencies between the data accessed at the file level and the location where the files are physically stored.

With File-level virtualization files can be moved very easily and it provides user or application independence from the location where the files are stored. This type of storage virtualization form a logical pool of storage and enable users to use a logical path, rather than a physical path, to access files.


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