In our column, “What’s Better than Cloud Storage for Cold Data”, my colleague George Crump discussed how cloud storage can be a cost effective alternative to onsite storage for active data, but where cold data is concerned it becomes a case of paying for the same real estate over and over again. The amount of capacity needed for cold data will only continue to increase over time, as will the monthly costs for storing it month after month, year after year. However, a lower cost effective alternative is readily available today; tape.
Why Tape Fell Out of Favor
Tape, for a variety of reasons, has been out of favor with organizations for quite some time now. Some of these reasons are erroneous, as we will see shortly. However, tape offers a much less expensive alternative for storing cold data with some additional compelling advantages that make it a very viable part of any organization’s data protection strategy.
Tape fell out of favor due to a combination of operational circumstances and the spread of various erroneous advertising pieces and Internet articles, as far back as 2006, that claimed a very high rate of tape recovery failures that were nevertheless accepted as factual. Let’s look at some issues that gave tape such a bad reputation.
Back in the 1990’s, DLT IV tapes were the de facto standard for all backup and archiving operations. By 2000, the first LTO-1 Ultrium tapes were released with a higher capacity and throughput than the DLT IV tapes. However, in that same time frame, the data tsunami had already started and organizations were facing shrinking backup and recovery windows while dealing with ever growing amounts of data to be stored and protected. Therefore, while tape technology met increasing capacity needs, it appeared to reach a point where it was struggling to meet backup and recovery performance expectations. In most cases, this was not a design flaw in tape itself but rather in the backup architecture. Tape requires a continuous feed of data for maximum performance and the architecture in the late 90s could not provide that.
With recovery times in particular becoming more critical than backup times, vendors started offering disk systems for backup and recovery operations. These disk systems soon offered robust features such as replication, data compression and deduplication. Eventually many would also add snapshot capabilities, which at that time were only available on primary storage. Consequently, disk based systems began pushing tape out of the data center.
However, more damaging than tape recovery speeds were various Internet articles and advertising pieces, referenced earlier, which were circulating at that time that stated that tape was not only slow but also unreliable where recoveries were concerned. One of the most damaging of these was the repeated claim that Gartner had supposedly stated that 71% of tape restores failed. There was also a purported report by the Yankee Group that claimed 42% of tape restores failed. This was repeated in another report supposedly from the group product manager for Microsoft’s Data Protection Manager Division, claiming the same 42% failure rate. Searches of both Gartner and IDC document libraries will not turn up any articles or research that supports these statements.
Back in the early 2000s time frame, I personally worked on a major long term e-Discovery project that involved scanning and recovering data from thousands of tapes that included DLT III, DLT IV and AIT-2 tapes with some tapes dating back to the 1990s. Out of all those thousands of tapes we scanned, there was only one actual physical tape failure because the DLT cartridge was damaged. There were several other recovery failures but they were due to some of the tapes in a given group having already been recycled before the court order came down to freeze all tapes. However, even in those instances, I was able to recover the data that was on the remaining tapes. In my experiences with this and various other projects over the last two decades, I have rarely encountered an actual physical tape failure that wasn’t due to human error in the backups or physical mishandling of the tapes.
Why Using Tape Makes Sense Today
Tape technology has come a long way since the days when DLT tapes were the de facto standard media for backup and archive. Today’s high quality, rugged LTO 6/7 cartridges combined with new media technology have made tape a far more reliable recording medium than ever with an archival shelf life of more than 30 years. There have also been significant improvements in performance with the new LTO 7 tapes, which provide a native capacity of 6.4 TB and a transfer rate of up to 315 MB/s. Support for the LTFS open format is another benefit which avoids the need for proprietary backup applications to recover data.
Among the many advantages of using tape are:
- Maintaining a proper chain of custody for data
- Portability which facilitates off-site storage for DR requirements
- Off-line storage provides better protection against malware and hacking attacks that can compromise data stored on disks within the enterprise
- Low one time acquisition cost
- Keeps size of needed disk and cloud repositories small by moving cold data off expensive disk
As many organizations realize the true costs of cloud storage where their cold data is concerned, many are trying to minimize their data footprint in the cloud by moving cold data back to local storage. However, all that data still needs to be stored and protected. Tape, when combined with a high performance disk front end, can provide the fast restore times needed while minimizing the amount of disk needed by migrating cold data to tape. Given the actual reliability and performance capabilities of tape today, as well as the low cost factor, organizations would be well advised to consider seriously, making tape a part of their total data protection strategy.
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