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Tape storage: lean and green – and still thriving
- 28 August, 2009 15:10
<p>By Lim Cheng Chuan, Country Manager (Australia & New Zealand), Tandberg Data</p>
<p>While the world’s huge volumes of data storage continue to expand, even in a global financial crisis, a less obvious trend is occurring in the use of preferred storage media.</p>
<p>Although the industry has been predicting the demise of tape for decades, tape continues to flourish as the preferred technology for medium to long term data storage. Disk is becoming the preferred medium to restore recently backed up files due to the speed of data accessibility, but the needs for long term business continuity, data protection and data archive are different.</p>
<p>Tape remains the solution for these due to six unrivalled attributes: portability, vast capacity in a small footprint, long lifespan, very low cost per gigabyte, high energy efficiency and scalability. Indeed, a new paradigm for tape storage is taking place.</p>
<p>Tape is robust and portable for easy offsite storage. Disaster recovery strategies recognise that keeping data backups on same site won’t protect information from site-wide disasters, so DR facilitators turn to tape storage for its robust, removable data with up to 1.6TB of data on a single LTO-4 data cartridge. Moreover, tape is compact, lightweight and robust for safe transport. WORM and hardware-based data encryption provide additional security and regulatory compliance.</p>
<p>Space and cost-efficient for longer term storage, tape offers a vast capacity in a small footprint. That capacity is essential as data volumes are predicted to escalate – six times the 2006 volume by 2010. Much is this explosion results from increasing compliance with legislation e.g. Sarbanes Oxley, HIPPA or the European Data Retention Act. Space constraints in the data centre also boost tape usage. Tape is preferred as it can be housed easily in a secure offline vault and exist offline without power or cooling requirements.</p>
<p>Compliance with legislation means generally that all data must be retained longer. Tape storage has proven life expectancy in normal conditions and has been shown reliable when tested to extremes. A 2007 report by Carnegie Mellon University recommended that CDs should be copied to new media every two years; hard disk drives every five years; DVD+RW every 5-10 years; removable disk every 10 years*; DAT media every 15 years; and LTO Ultrium media every 30 years.</p>
<p>Responding easily to the challenge of storing longer term archive data without breaking the bank, tape provides an exceptionally cost-effective $/GB ratio. LTO-4 Ultrium costs only 5 cents per GB for its typical capacity of 1.6TB, while DAT 160 costs 24 cents per GB for their 160GB cartridges, SATA hard disk drive 35 cents per GB for 500GB drives, DVD+RW 63 cents per GB for a 4.7GB disk and removable disk drive $1.45 per GB for the 160GB cartridges.</p>
<p>Tape is also energy efficient, in fact it is cool! Responding to the challenge of managing data centre power and cooling limitations, tape storage can decrease storage power requirements by 99 per cent. A 2007 study by The Clipper Group showed that the cost of energy to run a tape library was only 45 cents per terabyte, while energy costs for both SATA disk and VTL were $96 per TB. The energy required to store data on different tape media differs too – the Clipper Group reported that while LTO-4 required only .037 watts per gigabyte, LTO-3 needed .075 watts per gigabyte, DAT 160 required .128 watts and DAT 72 burnt up .197 watts of power.</p>
<p>Future scalability is another area where tape defies industry predictions by continuing to innovate. Consider the challenge of protecting an investment in technology by allowing for data growth over time. Over the years, tape has a stellar record in this area. Tape storage provides proven reliability, a wide range of capacity and performance points, backward compatibility for a seamless growth path, and tape libraries that offer even higher levels of scalability. Finally LTO’s robust roadmaps for LTO provide investment protection.</p>
<p>Protecting information is an absolute necessity for any business, although not all enterprises make it a priority. Developing the correct strategy means understanding the data and its value, and understanding cost saving tactics as well as the environmental impact and associated costs.
As tape technology continues to evolve to meet the archiving demands of today’s data centres, it is imperative that any storage strategy that is economical, environmentally responsible and designed for true data protection must include a tape solution.</p>
<p>Cost savings can be achieved with a realistic mix of disk and tape. Customer storage objectives are typically: performance/compliance/disaster protection/reduced TCO and energy costs. Blended tape and disk can address these objectives.</p>
<p>It is clear that the market has accepted a blended tape/disk strategy that ensues storage optimisation. Fleishman–Hillard research for the LTO Program shows that over 70 per cent of companies use disk and tape, while 52 per cent of them plan to increase tape usage. Up to 68 per cent of companies using disk-only storage plan to use tape. An IDC and IBM Marketing report shows that 70 per cent of the companies using disk and tape do so for interim storage, while 52 per cent plan to increase tape usage. Some 58 per cent use the media blend for long term archiving, while 51 per cent plan to increase tape usage.</p>
<p>The same report shows that companies using disk-only storage decreased 13 per cent last year: 58 plan to start using tape for interim storage, while 68 per cent intend to start using tape for long-term archiving.</p>
<p>Finally, in considering the environmental costs it becomes clear how ‘green’ tape is. After five years’ use, tape electrical costs are only 8 per cent of that tape’s acquisition cost. In comparison, disk electrical costs are 32% of acquisition costs after five years. A disk system costs 25 times more money to power and cool than a similar capacity tape system.</p>
<p>Take a scenario where you have 250TB of data with a 25 per cent growth rate over 10 years. Compare a DS4700 SATA disk with an LTO-1 tape library. Customer storage objectives are: performance, compliance, disaster protection and reduced TCO and energy costs.</p>
<p>Note that how very green tape is in comparison to disk – in this scenario tape uses 20 per cent less energy. However, an all-tape or all-disk solution may not address all goals. Tandberg Data research shows:</p>
<p>• SATA disk has up to 25 times higher energy costs than tape
• SATA disk costs about 6.5 times the cost of tape
• If electrical costs remain the same, the cost to acquire and power disk is 8 times the cost to acquire and power tape
• Energy costs must be a part of the TCO</p>
<p>Elements of a realistic storage strategy</p>
<p>IT resources should be allocated according to the value of data if optimisation is the goal. The highest value data, suitable for high performance disk storage, includes product inventory, shipments, sales, customer data, T&C, expenses and other business record. The risk: Business disruption, lost customer confidence, profit & revenue losses.</p>
<p>Medium value data, suitable for Nearline disk storage, includes last quarter’s material purchases, parts stock, held returns, quality measurements and other business records.
The risk: Lost backup, less accurate data analysis.</p>
<p>Lesser value data, suitable for tape storage, could be tax information, customer data, product serial numbers, and other business data. The risk: insufficient backup, possible government compliance issues, loss of evidence for potential litigation, embarrassment.
In any classification, information must have sufficient value to be securely stored and available when necessary. Failure to recover from a loss of data can cost millions in lost revenue.</p>
<p>Match the value of information with storage technology, and help to keep data retained and accessible when it’s needed. Today: an enterprise can move data to most cost effective storage for current use based on policies, while for the future they ought to move data to the most power efficient storage dynamically to satisfy usage requirements. An automated process will always reduce the cost of data storage.</p>