Buying Used Tape the Hidden Risks

Transcription

1 Buying Used Tape the Hidden Risks Considering Recertified Media? The concept of used tape has entered the market under the name of "recertified" or reconditioned. Cartridges that are sold as used are purchased from end users, sometimes run through a test process and sold for less than new, unused cartridges. Good business decisions for your data center should take precedent over the temptation to buy lower cost used tape. Understanding the Impact of Used Tape Buying used tape can put your company s data at risk. By introducing used cartridges into your data center, you may be introducing an unknown. You should consider a few questions. What will the media be used for? What is the value of the data being stored on this media? What performance specifications are required for your tape processing? The answers to these key questions are connected to the value of your mission critical data. Tape manufactures today offer high quality media designed for processing, storage and archive. Customers expect quality and performance because tape errors equate to time and money lost for the data center. When it comes to your valuable data, you cannot afford to risk not knowing where your media has been. Imation manufactures magnetic media under rigorous process controls--over 200 individual tests throughout the manufacturing process--to ensure product specifications are met for durability and archival stability. New media is manufactured to strict performance specifications; used media may or may not be certified to any performance specifications. Used cartridges may have been shipped with insufficient packaging materials, been exposed to an extreme environment or are approaching the end of their useful life. These problems can wreak havoc in the data center--easily negating any cost savings for the media itself. What is Recertification Some cartridges may be degaussed to erase data, but high capacity media cannot be degaussed as degaussing will erase the factory-written servo pattern. If degaussing is not used, a test pattern could be written to the complete length of the tape to remove all data. Considering the time it takes to write a test pattern to a standard high capacity tape, a mere four cartridges could be processed per drive in a standard workday (presuming maximum throughput can be maintained and no failures are encountered). So, how are these cartridges being certified? What criteria are they being measured against and what data remains on the tape? There is no single comprehensive test available that can verify what a cartridge has been exposed to technically, physically and environmentally. The question begs: Why buy used tape? Our goal in IT is to provide services to the business units that generate revenue. These businesses are increasingly demonstrating zero tolerances for down time. The processing and backup windows are being replaced

2 by 7x24 uptime requirements. We no longer have the luxury of time to waste on problems or errors, especially when we have the ability to avoid them. Cost of Job Reruns $400,000 $350,000 $365,000 $300,000 $250,000 $200,000 3 abends per week 1 abend per day $150,000 $156,421 $100,000 $90,000 $50,000 $0 $38,570 $30,000 $12,857 $429 $1,000 $3,000 $7,000 Daily Weekly Monthly Quarterly Annually Figure 1 Cost of job reruns over time based on an average abend cost of $1,000. How much can errors cost the data center? Studies show that the cost of a job ABEND can range from $375 to $6,775 and beyond, depending on the event. For our purpose we will work with an average ABEND cost of $1,000 per occurrence. If job ABENDS increase by just one per week from integrating used tape into your data center you could be spending over $50,000 annually in increased operating expenditures. (figure 1) Used media is the latest great unknown. Depending on the technology, today s media has a usage life expressed in full file passes or archival life expectancy. The archival life of magnetic media may reasonably be expected to have a lifetime of 15 to 30 years under normal usage conditions. Without the media usage and storage history, you cannot know what condition used media is in and how it will perform in your data center. Tests cannot show what used media has been exposed to before it was resold as certified. Much of what can be determined through a certification process will not expose the degradation of the expected life of the media. Tape damage may manifest itself over the remaining life of the media and may not have effects on the initial use of the media. An example could be a marginally performing cartridge that meets a published specification through a certification process, but exhibits excessive temporary errors, the silent killer in tape processing. By introducing marginally performing media

3 to your processing, you may be introducing the risk of data loss, job failure, or extending your job processing schedules to accommodate additional recovery time from temporary errors. Unfortunately we cannot go back and evaluate the environments that the used media came from. We cannot interview the staff and management from the shops that used the cartridges before the reseller bought them. We will never know how these tapes were used, stored or transported. All of this is extremely important to the expected life and successful use of tape cartridges. Proper Care & Handling Cartridges should be transported, stored, handled and used in operating environments that are clean and impart no stress or damage to the cartridges. However, we all know the perfect world is just beyond our reach. The most common cause of early end-of-life for a cartridge is attributed to physical damage through mishandling. Physical damage can impact the tape surface or tape edge and can result in cracked shells, split welds or missing components. The major contributors to physical damage include: Dropped cartridges during tape operations. Shipping and transportation of cartridges using inadequate packing. A good solution to proper packaging is utilizing the original manufacture s packaging. Packaging is design specifically for each tape technology format. A short video demonstration on appropriate packaging can be viewed at Drive maintenance and malfunction. Debris on the tape surface. Edge Damage Impact damage from shipping and transportation generally effects the edge of the tape. Edge damage may not result in immediate performance loss but will result in increased error counts over time that may impact job processing or backup schedules. (figure 2) Figure 2 Edge damage caused by impact.

4 Debris on Tape Today s technologies have track densities greater than 500 tracks per half-inch wide tape. Tracks are not only smaller, they are closer together and closer to the edge of the tape. Debris causing errors that were recoverable in the past may cause catastrophic problems today. 4 Tracks 1 Track Figure 3 Debris impact on data tracks Most debris contamination comes from within the data center, exposure during shipping and transportation or cross contamination from other problem cartridges. As with handling damage, the effects of debris contamination may not show up immediately and may take some time to develop into an evident problem in your processing. Even one piece of debris can become embedded into the surface of the tape resulting in a print through or image of the debris on adjacent wraps of the media in the tape pack. The tape drive has the ability in many cases to error-correct around a debris defect during a write operation, but after some time this image will cause distortion to the areas of the tape that were previously unaffected, now creating hundreds of errors. With the high track densities in today s tapes, debris that would likely not cause problems in the 1980 s and 1990 s can have serious, adverse impact on high performance, high capacity media. (figure 3) The Value of Data Over the past five decades tape capacity has grown to keep up with capacity demands. Capacities have grown at an incredible rate nearly doubling every 24 months on average. Capacities will most likely reach a terabyte on a cartridge in this decade. Why is tape so important? Because the tape media is where information lives. Data can spend a few hundred hours in a drive, but nearly 8,000 hours on the tape in a typical year running 24x7 operations. Consider the value of your mission-critical data before considering used tape for your data center applications.

5 Brian Avakian is a Data Center Solutions regional manager for Imation with 20 years experience managing the IT infrastructure for government projects and private industry for a major systems outsourcer. Today, Brian leverages past data center experience with data storage technology expertise to facilitate strategic and tactical planning and consultation for Fortune 500 data centers. James Goins has been with Imation for over 25 years and has over 21 years of experience working in the development, production, sale and support of magnetic storage media for mainframe, open systems, network and desktop applications. James expertise is derived from working closely with customers, OEMs and manufacturing to optimize media and system performance for all levels of magnetic tape drives.