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There are times in our interactions with customers where we hear the expression "tape is dead" and "nobody uses tape anymore". It often turns out, perhaps unsurprisingly, that this idea has been propagated by companies keen to sell their disk based alternatives and the customer is simply repeating it, believing it to be true. But is it true? Well last year, tape sales worldwide exceeded 20 exabytes (that's 20,000 petabytes) and were predicted to grow 25% this year. So it seems tape is not dead then; but where does tape score exactly - when should we recommend tape as a viable data storage medium?

Perhaps the best way to approach that is to look at the very attributes of tape that can make it attractive:

• Portability
• Cost per terabyte / running cost
• Reliability
• Environmental cost
• Storage density

In these areas tape scores well and indeed for large installations, i.e. multi-petabyte systems, careful use of tape can save over 80% of the cost of equivalent disk based storage over a 5-year lifecycle. Almost all large storage facilities use tape as a tiered layer within their ecosystems; disk is simply too expensive to buy and maintain, too heavy, too hot and in this day and age of rising energy costs, too expensive to run. When we consider that typically over 80% of the data we store is rarely or never accessed, it makes sense to ask why we would want to store that data upon a medium that is using up energy, when we can store it on tape where the energy footprint is a fraction of the disk equivalent.

Tape still has some tricks up its sleeve as well. This is perhaps best demonstrated by the arrival a couple of years ago of the LTFS standard, which shows just what tape can do. LTFS is a platform agnostic file-system written to tape. So sitting on a Linux workstation, we can write data to an LTFS format tape and post it around the country (or the world) to a Mac or a PC user (and vice versa) and they can put it into their tape drive and read the files off the tape into their system. A simple way to move up to 2.5TB (more if compressed) of data from place to place.

Trams advocates using Quantum Scalar Tape Libraries for a number of very good reasons. To begin with, the Quantum Scalar i500 tape library is the worlds most popular tape library, starting at just 41 physical slots (although activated/licensed quantity can be less), it scales to over 400 and fits in a standard 19" rack cabinet. Its bigger brother, the freestanding Quantum Scalar i6000, represents the pinnacle of intelligent, fault-tolerant high-density tape automation. Capable of scaling to 75 petabytes, with 780 tape slots per high density frame, up to 96 tape drives and with dual active-active wireless robots for trouble free running, the i6000 packs quite a punch. The dual robots ensure uptime, since failure of one robot triggers the remaining robot to push the failed unit out of the way, and replacement of the failed unit requires no application downtime and takes but a few minutes. With the industry's smallest footprint per cabinet and the largest load port density, the i6000 is an exceptional piece of technology. Supported by almost every backup application in existence, the Quantum Scalar range deliver very broad spectrum application compatibility, with all the enterprise features that the modern world demands, such as encryption key management, library partitioning and dual control and data paths to tape drives for fault tolerant fabric design.

These tape libraries can also be combined with storage tiering such as that provided by Quantum StorNext Storage Manager, where data that is least accessed on disk is migrated to tape; the user may still access the data, but it does not take up expensive disk space until they do. Staff continue to browse their drive mappings (or disks or mount points etc) just as they do normally, but when files that reside on tape are accessed, they are restored automatically to disk and made available to the user. Such hierarchical storage management (HSM) systems ensure that only the most important data is on spinning disk. Indeed, it is possible to construct entire systems where primary data is on fast disk, less used data is on secondary disk and as that secondary disk becomes full, data cascades onto tape where least-accessed files reside. Such systems ensure best use of expensive high performance primary disk whilst scaling the actual data pool into the multi-petabytes yet ensuring that power requirement (and cooling) are also kept to a minimum. Furthermore, because long term storage of data on tape can potentially mean that the tapes could fail and nobody would know until they were accessed, Quantum libraries in combination with StorNext Storage Manager proactively monitor tape health, and should a tape start to develop certain ill-health indicators, the library will automatically migrate the tape data to a fresh cartridge and update the controlling StorNext application to inform it of the change, thereby preserving both the data and access to it.

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