Types of Virtualization, Block and File level, comparison of both, protocols needed to implement these.

1. By Dr Mohammad Zunnun Khan

2.  Storage virtualization can be implemented in following ways.
 Each has its own advantages and disadvantages

3.  Virtualization on block level means that storage capacity is
made available to the operating system or the applications in
the form of virtual disks
 In virtualization on block level the task of file system
management is the responsibility of the operating system or
the applications
 The task of the virtualization entity is to map these virtual
blocks to the physical blocks of the real storage devices

5.  Virtualization on file level means that the virtualization entity
provides virtual storage to the operating systems or
applications in the form of files and directories
 The applications work with files instead of blocks and the
conversion of the files to virtual blocks is performed by the
virtualization entity itself
 This means, the task of file system management is performed
by the virtualization entity, unlike in block level which is done
by OS or application
 The physical blocks are presented in the form of a virtual file
system and not in the form of virtual blocks.

7.  Block-level storage is a type of storage commonly deployed by
larger businesses and enterprises in storage area networks (SANs)
and similar large-scale storage systems.
 Each block in a block-level storage system can be controlled as an
individual hard drive, and the blocks are managed by a server
operating system.
 Block-level storage protocols like iSCSI, Fibre
Channel and FCoE (Fibre Channel over Ethernet) are utilized to
make the storage blocks visible and accessible by the server-based
operating system.
 This is in contrast with file-level storage, in which the storage
drives are configured with a storage protocol like NFS or
SMB/CIFS.

8.  Another key difference between block-level storage and file-
level storage is that
 while individual files and folders can be accessed and managed
by the storage system in file-level storage, these storage
systems are unable to directly control the smaller storage
blocks that make up the files and folders.
 File-level storage is simple to implement and use, and it's also
less expensive to manage than block-level storage, which are
key reasons for it being the predominant storage technology
used on hard drives, network-attached storage (NAS) systems
and similar storage systems.
 In virtualization the only difference is these storages are created
by virtualization technology and so these storage does not have
a Physical devices its only virtualized

9.  Block-level storage virtualization is a storage service that
offers a flexible, logical arrangement of storing capacity to
applications and users while abstracting its physical
location.
 As a software layer, it catches I/O requests to that logical
capacity and maps them to the suitable physical locations.
 In computing, file virtualization is a field of storing
virtualization operating on the computer file level.
 It includes uniting multiple storage devices into a single
logical pool of files.

10. Thank you