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Mar 09 2016

Fast Petabyte-Scale Backups with Enhanced Security: ETERNUS LT260 and LTO-7


Contrary to assertions from self-proclaimed experts, "tape" still plays a key role in the backup, recovery and archiving strategies of numerous corporations large and small. For good reason: apart from the well-known cost advantage, modern tape libraries like Fujitsu's ETERNUS LT260 offer a wide variety of features one might not expect, such as built-in hardware encryption. And because it supports the LTO-7 standard, the LT260 is also ready to run in petabyte-scale storage and archiving scenarios.

Tape Technology and LTO
Although it has been pronounced dead on at least a few hundred occasions over the past 20 years, tape storage not only carries on regardless, but continually evolves. This seemingly unreal persistence is mainly owed to the fact that the technology has undergone rigid standardization: today, when you talk about tape you're talking about LTO, or Linear Tape-Open, a technology that was first introduced in the late 1990s and has since become the dominant force in the market. According to the Santa Clara Consulting Group's Back-Up Tape Tracker™, LTO accounted for 97% of all tape sales in Q4/2014. What's more, the 'old' technology has recently gained fresh attention from media and entertainment companies that have a reputation for their IT skills and prowess. For instance, DreamWorks Animation – producer of blockbusters like Shrek, Madagascar and How to Train Your Dragon – relies on what could be called a tape infrastructure for the long-term preservation of its massive movie and CGI portfolio. There's hardly a better proof for the fact that the optimum cost/capacity ratio can still be achieved with tape media. And prospects are good that it will stay like that for at least another decade.

As mentioned above, the main reason for LTO's ongoing success is standardization. Initially developed as a platform technology that would ensure interoperability between storage systems and media from different vendors, LTO followed a clear-cut roadmap almost from the start (cf. also Fig. 1 below). This roadmap included all features and functions that were considered essential for building a modern, competitive storage solution that would address modern data retention needs and still retain tape's greatest advantages – low cost, reliability, and simple shipping of media to and from a secondary site for disaster recovery. Meanwhile, LTO has reached its seventh incarnation (LTO-7), resulting above all in yet another massive capacity and performance boost: a single cartridge now holds up to 15 TB of information (compressed) and delivers sequential read/writespeeds of 750 MB/s, up from 6.25 TB and 400 MB/s in LTO-6.


Fig. 1: The famed LTO roadmap


Needless to say, the above information remains a little abstract unless it's connected to a tried and tested hardware platform, in this case our modular ETERNUS LT260 tape library. The library itself has been around for a number of years and during that time underwent regular upgrades as new LTO generations emerged, resulting in significant improvements whenever a cycle began. The new model follows the same pattern, with the following specifications and changes listed in the data sheet:

  • Capacity: The first ETERNUS LT260 models had room for 400 TB of uncompressed and 1 petabyte (PB) of compressed data. Those specs easily beat most rivaling libraries for medium-sized companies, which typically stored about one third of that amount. Next-generation models moved completely into the PB space, with total capacities ranging from 1.4 PB for uncompressed to 3.5 PB for compressed data in a full-fledged library with one base unit and six expansion modules. By incorporating LTO-7 technology, we raise the bar once again, this time to 1.2 PB of compressed data per base unit and a whopping 8.4 PB in the maximum configuration.
  • Data throughput and speed: As per usual with LTO, the increase in capacity is coupled with an elevation of transfer speeds, in this case by 87.5%. In our context, this means that a fully-configured latest-gen ETERNUS LT260 can achieve a total maximum throughput of 113.4 TB per hour if the data is compressed.
  • Backwards compatibility: Like any LTO-based tape storage device (and all other members of the ETERNUS LT family), the LT260 supports multiple variants of LTO technology, in this case LTO-7, LTO-6 and LTO-5. This ensures read/write compatibility with the previous generation and read compatibility with the penultimate generation of tape media. Put differently, depending on the individual setup users will be able to access data that was written to tape some six years ago – hard disks typically last between 36 and 48 months under optimum conditions.
  • Flexibility and ease of deployment: Each drive inside an ETERNUS LT260 connects to hosts either via an 8 Gb/s FC or a 6 Gb/s SAS interface. The former enables high throughput that helps to drastically reduce backup times, while the latter allows for building flexible or even tiered storage architectures at relatively low costs. What's more, the ETERNUS LT260 supports the entire range of open systems servers regardless of CPU type and operating system, i.e. any x86 or SPARC server running supported versions of Windows, Linux or Unix. Likewise, it cooperates with all popular software solutions from leading vendors like Symantec, CommVault, EMC or CA. In short, the ETERNUS LT260 will swiftly integrate into almost any given backup and archiving environment.
  • Easy expandability and high density: As noted above, the ETERNUS LT260 builds on a "modular concept," which means that customers can start with a fully functional base unit that has all necessary components pre-installed. Each of these units comes equipped with up to six tape drives and slots for up to 80 tapes. This basic configuration may be expanded with up to six additional modules providing identical capacities, thus arriving at a total of 42 tape drives, 560 tape slots or 8.4 PB storage space (see above). Moreover, since all slots within a module are activated by default, there are no hidden upgrade costs, thus ensuring the ETERNUS LT260 provides excellent investment protection.
  • Ease of use and ease of management: Although many midsize companies run their own IT departments, they often don't have enough storage experts – and in particular tape storage experts – on board. That's why the ETERNUS LT260 adds a number of components and features that make it simple to operate, maintain and manage even with a small staff or limited skill set. For example, it offers removable mail slots (up to 10 per module) that simplify importing, exporting or exchanging single tapes and cleaning cartridges. Probably the most interesting software feature is the logical library function, which allows admins to 'split up' each unit into as many as six partitions or subsystems that may then be used as dedicated backup or archiving units for different server groups or application environments in parallel. And as some kind of icing on the cake, the entire setup can be remotely and centrally managed using an intuitive browser GUI with numerous automation options – so there is practically no need for on-site tape storage experts at all.

Data Security
In today's information-driven economy most, if not all, companies consider 'their' data to be their most important asset that must be protected from unauthorized access at all times. One way to achieve this is through encryption of stored data; so it was only logical for the LTO standard to incorporate encryption at some point in time. That point was finally reached when LTO-4 appeared in 2007; since then, all member of the ETERNUS LT family have supported various encryption and key management mechanisms. Over the years, our offerings have matured, and nowadays customers can choose between different encryption options to achieve adequate protection levels. The standard (read: most widely spread) method would be to rely on encryption mechanisms provided with popular backup programs such as Symantec NetBackup , CommVault Simpana etc., which usually include a host of related functions. The inherent weaknesses of this approach are twofold. On the one hand, the process of encrypting will inevitably slow down the backup application's performance. On the other, potential adversaries could always try to trick vulnerable backup software modules into revealing details about the mechanisms and/or keys in use.

Customers who demand a higher level of security can instead opt for using the Key Management Interoperability Protocol (KMIP), a standard for exchanging encryption keys over a network that enables admins to deploy a single, consistent key management system to various devices in the data center. Even better: with KMIP activated, security staff can predefine the encryption settings for the ETERNUS LT260 in question and assign to it one master key, which in turn serves as the basis for automatically generated encryption keys for each data cartridge. Both the master key and the individual encryption keys may be stored in a database within the library. During backup, the library automatically assigns an encryption key to a specified tape, encrypts the plaintext, and saves the data. The encryption process during this time is invisible to users. That way, administrators can easily set up a secure backup environment that is independent from both the OS(ses) and the application(s) running on the backup server(s). With the latest ETERNUS LT260 models, that's even easier to do, as the entire process – from key generation to encryption and back – can now be handled inside the library. In other words, IT departments no longer need to operate dedicated key servers, and the need for human interaction is kept to a minimum – so users may save money and still feel more secure.

With its 8.4 PB maximum capacity, exemplary expandability and unprecedented ease of use, the ETERNUS LT260 is highly attractive for midsized companies looking for a backend system to satisfy both their backup and long-term data retention needs. Possible use cases include consolidated backups of several types of aggregated, company-wide backups (e.g. of data stored on disk arrays and NAS filers); backups for server clusters running mission-critical tasks; fast and simple disaster recovery; and finally centralized 'recording' and archiving of disk backups from ROBO environments.

Stefan Bürger


About the Author:

Stefan Bürger

Head of Tape Automation at Fujitsu


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