A virtual tape library (VTL) is a

data storage Data storage is the recording (storing) of information (data) in a storage medium. Handwriting, phonographic recording, magnetic tape, and optical discs are all examples of storage media. Biological molecules such as RNA and DNA are con ...

virtualization In computing, virtualization (abbreviated v12n) is a series of technologies that allows dividing of physical computing resources into a series of virtual machines, operating systems, processes or containers. Virtualization began in the 1960s wit ...

technology used typically for backup and recovery purposes. A VTL presents a storage component (usually hard disk storage) as tape libraries or

tape drive A tape drive is a data storage device that reads and writes data on a magnetic tape. Magnetic-tape data storage is typically used for offline, archival data storage. Tape media generally has a favorable unit cost and long archival stability. ...

s for use with existing backup software. Virtualizing the disk storage as tape allows integration of VTLs with existing

backup software In information technology, a backup, or data backup is a copy of computer data taken and stored elsewhere so that it may be used to restore the original after a data loss event. The verb form, referring to the process of doing so, is " back up ...

and existing backup and recovery processes and policies. The benefits of such virtualization include storage consolidation and faster data restore processes. For most mainframe data centers, the storage capacity varies, however protecting its business and mission critical data is always vital. Most current VTL solutions use SAS or

SATA SATA (Serial AT Attachment) is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the earlier Parallel ATA (PATA) standard ...

disk array A disk array is a disk storage system which contains multiple disk drives. It is differentiated from a disk enclosure, in that an array has cache (computing), cache memory and advanced functionality, like redundant array of independent disks, RAID ...

s as the primary storage component due to their relatively low cost. The use of array enclosures increases the scalability of the solution by allowing the addition of more disk drives and enclosures to increase the storage capacity. The shift to VTL also eliminates streaming problems that often impair efficiency in tape drives as disk technology does not rely on streaming and can write effectively regardless of data transfer speeds. By backing up data to disks instead of tapes, VTL often increases performance of both backup and recovery operations. Restore processes are found to be faster than backup regardless of implementations. In some cases, the data stored on the VTL's disk array is exported to other media, such as physical tapes, for

disaster recovery IT disaster recovery (also, simply disaster recovery (DR)) is the process of maintaining or reestablishing vital infrastructure and systems following a natural or human-induced disaster, such as a storm or battle. DR employs policies, tools, ...

purposes (scheme called ''disk-to-disk-to-tape'', or ''D2D2T''). Alternatively, most contemporary backup software products introduced also direct usage of the file system storage (especially

network-attached storage Network-attached storage (NAS) is a file-level computer data storage server connected to a computer network providing data access to a Heterogeneous computing, heterogeneous group of clients. In this context, the term "NAS" can refer to both th ...

, accessed through NFS and CIFS protocols over IP networks) not requiring a tape library emulation at all. They also often offer a

disk staging Disk staging is using disks as an additional, temporary stage of backup process before finally storing backup to tape. Backups stay on disk typically for a day or a week, before being copied to tape in a background process and deleted afterwards ...

feature: moving the data from disk to a physical tape for a long-term storage. While a virtual tape library is very fast, the disk storage within is not designed to be removable, and does not usually involve physically removable external disk drives to be used for data archiving in place of tape. Since the disk storage is always connected to power and data sources and is never physically electrically isolated, it is vulnerable to potential damage and corruption due to nearby building or power grid lightning strikes.

History

The first VTL solution was introduced by Cybernetics in 1992 under the name HSTC (high speed tape cache). Later, IBM released a Virtual Tape Server (VTS) introduced in 1997. It was targeted for a

mainframe A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterpris ...

market, where many legacy applications tend to use a lot of very short tape volumes. It used the

ESCON ESCON (Enterprise Systems Connection) is a data connection created by IBM, and is commonly used to connect their mainframe computer A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large o ...

interface, and acted as a disk cache for the IBM 3494 tape library. A competitive offering from StorageTek (acquired in 2005 by Sun Microsystems, then subsequently by Oracle Corporation) was known as Virtual Storage Manager (VSM) which leveraged the market dominant STK Powderhorn library as a back store. Each product line has been enhanced to support larger disk buffer capacities, FICON, and more recently (c. 2010) "tapeless" disk-only environments. Other offerings in the mainframe space are also "tapeless". DLm has been developed by EMC Corporation, while Luminex has gained popularity and wide acceptance by teaming with Data Domain to provide the benefits of

data deduplication In computing, data deduplication is a technique for eliminating duplicate copies of repeating data. Successful implementation of the technique can improve storage utilization, which may in turn lower capital expenditure by reducing the overall amou ...

behind its Channel Gateway platform. With the consequent reduction in off-site replication bandwidth afforded by deduplication, it is possible and practical for this form of virtual tape to reduce recovery point objective time and recovery time objective to near zero (or instantaneous). Outside of the

environment, tape drives and libraries mostly featured

SCSI Small Computer System Interface (SCSI, ) is a set of standards for physically connecting and transferring data between computers and peripheral devices, best known for its use with storage devices such as hard disk drives. SCSI was introduced ...

. Likewise, VTLs were developed supporting popular SCSI transport protocols such as SPI (legacy systems),

Fibre Channel Fibre Channel (FC) is a high-speed data transfer protocol providing in-order, lossless delivery of raw block data. Fibre Channel is primarily used to connect computer data storage to Server (computing), servers in storage area networks (SAN) in ...

, and

iSCSI Internet Small Computer Systems Interface or iSCSI ( ) is an Internet Protocol-based storage networking standard for linking data storage facilities. iSCSI provides block-level access to storage devices by carrying SCSI commands over a TCP/IP ...

. The FalconStor VTL is the foundation of nearly half of the products sold in the VTL market, according to an Enterprise Strategy Group analyst. In mid-2010s VTLs got a rebirth thanks to hi-capacity "archive" drives from Seagate and

HGST HGST, Inc. (Hitachi Global Storage Technologies) was a manufacturer of hard disk drives, solid-state drives, and external storage products and services. It was initially a subsidiary of Hitachi, formed through its acquisition of IBM's disk driv ...

and more popular "tape in cloud" and Disk-to-Disk-to-Tape (often in cloud) scenarios.

Amazon Amazon most often refers to: * Amazon River, in South America * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon (company), an American multinational technology company * Amazons, a tribe of female warriors in Greek myth ...

and StarWind Software in partnership with Veeam,

BackBlaze Backblaze, Inc. is an American cloud storage and Backup, data backup company based in San Mateo, California. It was founded in 2007 by Gleb Budman and others. Its two main products are their B2 Cloud Storage and Computer Backup services, targete ...

and Wasabi Technologies offer a so-called gateway products that facilitates backing up and archiving "on premises" data as virtual tapes stored in AWS,

Microsoft Microsoft Corporation is an American multinational corporation and technology company, technology conglomerate headquartered in Redmond, Washington. Founded in 1975, the company became influential in the History of personal computers#The ear ...

Azure, Wasabi Technologies and

public clouds. The idea is to provide a seamless integration of a backup applications incompatible with the APIs object storages expose. Say, at the time Veeam couldn't do AWS S3 and can't backup to the deep archive tier within Azure still.

References

{{Operating System Tape-based computer storage Backup

History

See also

References