Magnetic tape - the old horse does not spoil the furrow

    Each time we meet the phrase data center, or the abbreviation DPC (data center), our consciousness instantly “pulls from the cache” a set of standard patterns that would seem quite unambiguously associated with this characteristic representative of modern IT infrastructure. Spacious rooms, server racks - strewn with splashes of multi-colored LEDs, the buzz of power supplies competing with even stronger noise from the hood, which removes excess heat from the halls, twisted bundles of cables of various diameters and colors, engineers dissecting with important views along narrow corridors between the walls, lined with high-tech equipment. What to speak of huge electricity bills, it all seemed so natural and uncontested. I will not disappoint anyone, in general, the way it is, in 99% of cases.

    At the end of 2014, Spectra Logic, one of the IBM divisions, announced the creation of the fifth generation of the 3592 series cartridge cartridges (type D), model 1150. This development allows storing up to 10 TB of data, the read speed from the media has reached an impressive 360 ​​MB / s. Moreover, this cartridge is compatible with all existing IBM tape libraries since the 90s. Data center and tape media, how do these two concepts fit together in a world where HDD and SSD dominate? At the beginning of the article, we recalled the classic data center, of which there is indeed an absolute majority, but that small percentage of IT nodes remains, an integral part of which has become, many of us, well-forgotten, magnetic tape.


    Data centers in which the bet was placed on magnetic tape, as the main data carrier, of course did not appear today. Back in the 1950s, at the dawn of the beginning of the industrial exploitation of such carriers, they quickly gained popularity, and there were quite objective reasons for that. First and foremost, this is the ratio of the volume of data posted and the dimensions of the medium. By the way, the first tape libraries contained no more than 2.5 MB of data, but in production they were much simpler and cheaper than the first HDD solutions. Also, this technology made it possible to use a fairly wide range of materials, which, at a very reasonable price, could become a reliable haven for decades for binary-encoded data. In fact, that’s how it has been for decades,

    Let’s take a closer look, thanks to which tape drives, such dinosaurs from the time of the creation of the digital world, not only survived to our century, but also remained in demand for consumers of the IT infrastructure market. As at the very beginning of the use of tape magnetic drives, at the moment they have one of the best price-volume-compactness-durability ratios. But do not forget the fact that, in addition to obvious advantages, the technology mentioned also carries certain difficulties that significantly limit the range of use of tape media. It is obvious that the cartridge recently introduced by Spectra Logic, this brainchild of our time and with its predecessors from the 50s, has similarities based only on the principles of technology organization.

    Tape Libraries

    The “tape library” combination that came from it was something more than a cabinet with systematized cassette units stored there. Now there are a number of manufacturers of such IT equipment on the market, the largest of them are IBM, Dell, HP, Compaq, Fujitsu - the real flagships of our time in the high-tech industry. As a result, the complexity of the products and the ability to integrate them into the most modern systems have reached real heights. Modern automated libraries completely exclude human intervention in their activities, the speed of processing cartridges, due to the progress of mechanical structural elements and a software product, has become acceptable for organizing autonomous backup services based on libraries. Also, most libraries, say a manufacturer like HP, can be equipped with an external SCSI or Fiber Channel interface, and this in turn allows you to receive and transmit significant amounts of data. Interfaces for high-speed data transmission have long been a necessity for such solutions. Prior to the recent Spectra Logic presentation of the Model 1150 tape cartridge, with 360 MB / s reading speed, cartridges with a maximum speed of around 250 MB / s were widely used, which was not critical by itself for transferring large amounts of data, as well as the reason for using several readers in automated libraries.

    As for the minuses of tape storage systems, they are very predictable. A central problem is the limited multi-user access to information in libraries. This is especially aggravated by the fact that another section of the library can easily accommodate 600 TB. Another very limiting factor is the sequential recording of information on cassette media, which naturally excludes the possibility of instant access to several data arrays.

    Based on the strengths and weaknesses of the technical implementation of systems that are created on the basis of tape drives, they, in turn, have become an ideal storage for backups. They also found their application in research institutes, and became an integral satellite of "super computers" generating petabytes of data. The explosion in the growth of high-definition television also played a significant role in the demand for “magnetic tape”; thousands of hours of capacious video material created by multimedia companies left no alternative to cartridge cartridges. Companies that own cloud services are also among the customers of this technology. The impressive growth of the “clouds” put the company's data before the reality of operating with huge data arrays within the boundaries of complex systems, which are based on the basis of many clusters, and this, in turn, makes it possible to implement the cheapest storage medium at the moment - magnetic tape. According to various estimates, 1 GB, high volume, tape media costs the buyer only 4 cents, against 10 cents for similar HDD media. When it comes to energy consumption, the usual HHD and SSD are simply not competitors to the tape. “Cold storage” of data, and of course the lack of high heat generation, gives the right to call automated libraries the most energy-efficient integrated solutions for long-term data storage. When it comes to energy consumption, the usual HHD and SSD are simply not competitors to the tape. “Cold storage” of data, and of course the lack of high heat generation, gives the right to call automated libraries the most energy-efficient integrated solutions for long-term data storage. When it comes to energy consumption, the usual HHD and SSD are simply not competitors to the tape. “Cold storage” of data, and of course the lack of high heat generation, gives the right to call automated libraries the most energy-efficient integrated solutions for long-term data storage.

    The fact that automated libraries were able to operate within the boundaries of one operating system made it possible to very easily scale such storages, making it possible to combine dozens of disparate devices into a single structure.

    CERN's network engineer, Micke Collin, speaks about the implemented node, mainly using tape technology: “There is no adequate tape replacement in our farm. As a result of our work, on the basis of the larger hadron collider, on the study of the structure of matter, colliding protons and ions at huge speeds, a huge amount of data arises. Not only do the experiments themselves involve recording all the information on the collision of millions of particles per second, moreover, we have been forced to store all this information in our data centers for years. From the very beginning of the organization of work, the task was to minimize the loss of resources for storing and processing petabytes of data obtained as a result of multimillion-dollar costs. And in this the magnetic tape became the faithful assistant. ” Focusing on the characteristic features of ribbon cartridges, Mike noted: “The uniqueness of the tape lies in the fact that in the event of a media breakdown, it has a much greater potential for recovery than its competitors. There were times when, for various reasons, the cartridges failed and we lost pieces of tape, but after removing the damaged area and gluing the surviving ends, we had access to the vast majority of the information on the cartridge, at the same time confronted with malfunctions in the SSD and HDD, there were precedents for the loss of the entire data array located on the disk. "

    Naturally, the technology involving the storage of information on magnetic tape does not appear to be a completely independent, self-sufficient data carrier in modern data centers. At the same time, it is an excellent complementing element of the network infrastructure, allowing you to save significant money both at primary costs and during operation. The development of this technology also speaks of its relevance in the IT industry market, making it even more interesting for owners of large organizations that are forced to interact with especially large amounts of information in their activities. Having begun its formation in the mid 30-ies of the twentieth century and now this way of storing data looks absolutely relevant, in addition, it has all the makings of a continued successful existence.

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