07 March, 2023
LTO Superpowers: Longevity and Reliability
Super LTO, the hero product?
LTO Superpowers are its dependable performance, extended lifespan, and minimal energy usage. In this the final blog in the series, which has covered the key questions raised as a result of the video from Gavin Slow Mo Guys of YouTube fame, where he discussed his struggle to secure 10 years of content, and how he turned to LTO to help solve this challenge. Our examination will encompass not just the exceptional dependability and durability of LTO media, but also it's standing as the most environmentally-friendly storage technology currently in use.
Our first blog in the series “Death, Taxes and Data Loss”, discussed the general need for data protection, the difference between backup and archive and why they are equally important, but often confused. In the second blog of the series “Tape is Dead. Long Live Tape?”, we dispelled the myth that tape is dead, and in fact went a long way to prove that it is likely to win out in the capacity battle between LTO and HDD over the next ten years or so. We encourage you to consider that it may make sense to invest in LTO versus that ever-growing mountain of hard drives, or indeed public cloud storage solutions. But remember, no man, or in this case, data protection strategy, is an island.
This blog post will examine the reliability of tape compared to hard disks, the longevity of LTO, the necessary precautions to ensure its optimal lifespan, and also explore the eco-friendliness of the technology.
So is tape more reliable than a hard disk? This is one of the questions we are asked most frequently, and the short answer is yes, and here’s why. The high reliability of LTO technology stems from the data redundancy strategies employed to check that the data being written to the tape is correct. LTO uses something called Error Correction Code (ECC), which is generated at two levels (C1 and C2) to protect data written to the tape. C1 and C2 are highly efficient Reed-Solomon ECC, commonly used to protect data on storage systems. C1 is designed to detect and correct media errors, and C2 operates as an Erasure code to correct any residual errors from the C1 process. So these codes are added to the data, before it is written to the tape and then verified after it is written, to ensure an extremely low bit error rate (BER). But how low can it go, I hear you ask? 1 error event in 10-19 bits, and that is a very, very small number. So to put that number in context, it would take 130 tape drives, each writing data continuously for a whole year before any of them would encounter an that could not be fixed by the error correction technology employed by LTO.
In contrast to a hard disk that generally has a bit error rate of 1 error in 10-15 bits. Let's not kid ourselves, this is still a small number, but it does mean that LTO is some 10,000 times more reliable than hard disks, and even 1000 times more reliable than SSD. To put it another way the odds of getting an uncorrectable error using LTO media are some one in 10 quintillion, the odds of getting hit by lightning are one in a million, getting killed by a shark one in 11.5 million (unless you live in Martha’s Vineyard), or one in 259 million for that dream lottery win (I must remember to get my ticket).
Another advantage of LTO is its impressive life span, which the LTO consortium publicises as up to 30 years. This is significantly longer than the life span of even an enterprise hard drive. I was recently at an event with Pro Device Global, a company that specialises in Cybersecurity Strategies. They had been tasked to recover data from a large archive of reel-to-reel tapes, some of which were 50+ years old. Although the tapes had been stored at a relatively constant temperature, no other precautions had been taken, which meant that the tapes were in a poor condition… but a staggering, 98% of the data on the tapes was still recoverable. As a side note, Pro Devices believe the only way to irreversibly erase data from an LTO tape is by using a powerful pulse of induction of up to 22,000 Gauss (2.2 Teslas).
Therefore, let us examine the lifespan of a hard drive. This graph, courtesy of the team at BackBlaze (who have been helpfully publishing hard drive reliability since 2013 - https://www.backblaze.com/b2/hard-drive-test-data.html), shows their current figures for annualised failure rate of all the hard disks they use.
The annualised failure rate from the start of 2018 through to the end of 2022 is 1.37% across 230,921 enterprise class drives from various vendors (but not consumer or NAS drives, which are less reliable and are not used by public cloud providers). Back in 2013 the data shows that 80% of the installed drives would be expected to survive for four years, this fell to 50% after six years. So after 6 years only half of the originally installed hard drives were still working. In 2021, the life expectancy of a hard drive being alive at six years was 88%. This data suggests that although drive reliability has increased, as you might expect over time, it is still nowhere close to the reliability of an LTO cartridge.
It is important to note that these statistics are for enterprise-grade hard drives that are part of large storage systems designed to optimise the environment for hard drives (minimising vibration and heat) and incorporate protection measures such as Erasure Coding and RAID. These hard drives are in constant operation 24 hours a day, 7 days a week. Hard drives used in smaller multi-bay systems or single drive systems usually spend the majority of their time turned off, which is not great for a hard drive. This increases the chance of mechanical failures, and without the hard drive being powered on, the error correction technologies employed by hard drives to protect against bit rot (the slow deterioration in data integrity of data stored on storage media) are not active. This means that the disk is more prone to mechanical failure, along with an increased risk of the data corrupting over time. Of course you could plug in all your hard drives every six months to test them, but who has the time to do that? Perhaps better to live in blissful ignorance, and hope for the best!
Let's return to the impressive 30 year life span of LTO. The lifespan of an LTO tape does depend on the usage, as well as how the tapes are actually stored long-term, when not in use. In terms of operation, LTO is generally good for 300 full-file passes (reads or writes), 20,000 short-section durability passes, and 20,000 loads and unload cycles (for half-height drives), which is a lot of operations! As a general rule, LTO tapes only need replacing in very high volume backup applications (think of banks and other large corporations), where there is a high degree of change occurring as backup sets are appended and tape sets are reused again and again. Typically, much of the data written to LTO in a media environment is relatively static, so the number of reads and writes are not relevant. Always remember to follow the 3-2-1 rule for best practice data protection, your content is not secure if the only copy is on a single LTO cartridge.
In terms of storing data tapes for long periods of time, it varies a little from generation to generation, but as a rough rule of thumb LTO tapes should be stored between 15°C to 25°C (59°F to 77°F), in humidity levels between 20% to 50% (non-condensing, with a 22°C dew point maximum). The LTO data cartridges can easily be shipped and can tolerate much more extreme temperature conditions for those shorter periods of time, for example -23°C to 49°C.
The LTO cartridges are robust and can be transported, but care needs to be taken to make sure they are packed correctly. Always ship and store the data cartridge in a jewel case, typically cartridges always come in a jewel case, unless they are being used in tape library applications, where they come in a library pack, which provides the appropriate protection. If you are shipping the cartridges make sure they are securely packed in their original packaging material or better. There are various hard plastic cases solutions on the market, certified for transporting up to 20 tapes at a time, that are extremely robust.
Before using a cartridge it is very important to let it acclimatise to the normal operating environment for a minimum of 24 hours. At Symply, we typically recommend keeping the drive and media storage together for this acclimatisation period. Before inserting the cartridge into a tape drive there are some very simple checks to carry out to ensure good operation. Firstly, ensure that all surfaces of a cartridge are dry (this goes to the point of acclimatisation), check for signs of damage to the cartridge (cracks in the plastic), you should also check the cartridge door is not damaged. If you do drop a cartridge, it is important to open the cartridge door and check that the leader pin is properly positioned inside an LTO tape cartridge, if the leader pin is out of position it can interfere with the operation of the drive.
More detailed guidance on handling and storing LTO media can be found at https://support.gosymply.com/support/home
Many organisations the world over are also embracing the drive to Net Zero emissions, and there is no greener storage media in terms of emissions. This applies to both the manufacturing process versus a hard drive, but also to the operating costs of the storage. There is no doubt that LTO offers a huge saving in energy consumption. Tape drives use little power when not reading or writing tape cartridges, and a tape cartridge in a library or stored on a shelf uses no power at all. It is estimated that 1PB of tape storage (in a library) uses 300 watts, while 1PB of HDD storage uses about 3500 watts. The LTO.org estimate that simply converting 33% of disk storage to tape could save 200 million megawatt hours per year globally. That’s enough energy to drive an electric car some 7,200,000,000 miles (next stop Neptune).
I hope what you have gained from this blog series is that, above anything else, it is really important to implement a robust data protection strategy. Employing the correct data protection strategies means that your data can remain protected in the event of system failures, malware attacks, data security breach, user error, or the corruption of media over time. Remember there are two types of people: those that have experienced data loss and those that will. LTO is a fantastic medium for protecting data, due to its cost, reliability, longevity, lower power consumption, and ease of transport. Tape is far from dead; on the contrary, it is going to outperform hard disks in terms of capacity over the next decade, growth that is being driven by the hyperscale cloud providers. So the irony is that even if you don’t own a tape drive or media, if you own a smartphone then you use tape, you just don’t know it.