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Tape trends As always, the main trend in the tape market is the inexorable march toward higher capacity and faster transfer rates, a trend exemplified by the imminent arrival of LTO-4 tape drives, libraries, and media.
The Linear Tape-Open (LTO) Program announced the availability of licenses for the LTO Ultrium tape format generation 4 (LTO-4) specifications in January. (The LTO Program consists of Hewlett-Packard, IBM, and Quantum, although Tandberg also manufactures LTO drives.) Estimates vary, and are vendor-dependent, but you can expect LTO-4 libraries from a number of vendors to ship over the next couple of months—although volume may be limited by drive supplies from the primary drive manufacturers). IBM, Qualstar, and Spectra Logic, for example, were expected to begin shipments of LTO-4 tape libraries this month. LTO-4 provides a native capacity of 800GB (1.6TB assuming 2:1 compression), representing a doubling of LTO-3’s 400GB native capacity per cartridge (see figure on p. 1). The native transfer rate of LTO-4 drives is 120MBps (240MBps compressed), compared to 80MBps for LTO-3. A native transfer rate of 120MBps roughly translates into a backup rate of 864GB per hour. The doubled capacity and increased transfer rate of LTO-4 will enable companies to better manage their backup windows, reduce space consumption in data centers, improve library utilization, and reduce the amount of tape handling by administrators and robotics mechanisms.
LTO-4 will continue to support the write-once, read-many (WORM) functionality that debuted in LTO-3 products. And LTO-4 will be backward read/write-compatible with LTO-3 cartridges, and backward read-compatible with LTO-2 cartridges.
In addition to the capacity and speed improvements, as well as WORM support, LTO-4 will for the first time support 256-bit hardware-based AES encryption (see below). The introduction of LTO-4 is expected to cement the format’s dominance in the midrange tape market. LTO-based tape libraries accounted for approximately 88% of the shipments of midrange libraries last year, up from about an 84% market share the previous year (see figure, above). That translates into more than 55,000 LTO libraries shipped in 2006 and revenues of about $1.26 billion.
LTO library/autoloader manufacturers include Breece Hill, Fujitsu, IBM, Overland Storage, Qualstar, Quantum, Spectra Logic, Sun/StorageTek, and Tandberg (which acquired tape drive/library manufacturer Exabyte last year). LTO media manufacturers include vendors such as Fujifilm, Imation, Maxell, Sony, and TDK. For more information on LTO technology and products, visit www.ultrium.com. But tape format “speed and feeds” aren’t the only trends in the tape market. Other trends include increased use of WORM technology due to the need to meet data-retention requirements and other compliance regulations and, perhaps more importantly, a variety of options for tape encryption. WORMWORM functionality is becoming available on an increasing number of tape formats, including LTO-3 and LTO-4, half-inch tape cartridges from vendors such as IBM and Sun/StorageTek, Quantum’s DLT line, and most AIT versions, including the most recent generation—AIT-5—which has a native capacity of 400GB per cartridge and a native transfer rate of 24MBps. WORM can be enabled either through the selection of the unrecorded media, or by specifying the writing mode of the cartridge at the time of initial cartridge insertion. Most vendors take the former approach, which means that users require specialized media for WORM functionality. WORM media typically carries a 5% to 10% price premium. Quantum’s DLTIce technology is an exception to this rule, in that it does not require specialized media. Essentially, DLTIce software, which is supported by firmware in DLT tape drives, provides the ability to lock a tape cartridge as a WORM device. Creating a WORM cartridge involves writing a unique electronic key that cannot be altered on the DLTtape cartridge. The identifier creates a tamper-proof archive cartridge. Once turned into a WORM cartridge, the media cannot be erased or reformatted. EncryptionThe availability of native, drive-level hardware encryption on LTO-4 drives—which is unique among midrange tape formats—is expected to spark further interest in encryption. However, there are a number of other options available. Outside of what is generally regarded as the midrange tape segment, IBM and Sun/StorageTek offer native, drive-level encryption on some of their half-inch tape products. And Spectra Logic has since late 2005 offered hardware-based, library-level encryption (which is unique among tape library vendors). The hardware part of Spectra Logic’s AES 256-bit encryption scheme is based on encryption chips from Hifn that run on Quad Interface Processors (QIPs), which are I/O blades that plug into Spectra Logic’s tape libraries. Key management, and other encryption-related functions, is handled by the company’s BlueScale management software. Although debates about where to encrypt might ensue, Bob Abraham, president of the Freeman Reports tape market research firm, says that “there is no particular advantage to native drive-level encryption vs. encryption at the library level in terms of performance or security.” But even Spectra Logic notes that there are advantages to drive-level encryption outside of performance and security. “The best way to do encryption is in the drive, in part because you’ll have universally interchangeable tapes [as opposed to being locked into a single vendors’ encryption method,]” says Nathan Thompson, Spectra Logic’s CEO. When LTO-4 drives with encryption become available, Spectra Logic will use the drive-level encryption for LTO-4 cartridges, but will continue to use its own encryption method for previous LTO generations. In either case, the company’s key management will depend on its BlueScale Encryption management software. (A Standard Edition of BlueScale Encryption software is free, while a Professional Edition is priced from $12,000 and includes extra layers of security, compression, and support for multiple keys.) Peri Grover, Overland Storage’s director of product management, tape automation, agrees that key management will be a critical factor in end-user adoption of encryption, but she disagrees about where the key management should come from. “Some users get nervous about key management, and that can be a gating factor to adoption of encryption,” says Grover. “We think that key management should come from the ISVs [CA, CommVault, EMC, Symantec, etc.] so the question will be whether the ISVs support key management when the LTO-4 drives with encryption come out. They’re all working on it.” In the context of LTO-4 drive encryption, it is important to note that the LTO-4 specification does not require encryption; it just enables a standardized method of accomplishing it. As such, don’t be surprised if some of the early versions of LTO-4 tape drives do not include encryption. Also, it is expected that drive-level encryption will carry a price premium, although it’s unclear at this time how steep the premium will be. Other encryption options include dedicated, stand-alone appliances such as those from Decru and NeoScale. These appliances provide high-speed encryption and sophisticated key management, although they are relatively expensive. Yet—another alternative is a recently introduced appliance from Crossroads Systems. At last month’s Storage Networking World conference, Crossroads introduced the StrongBox TapeSentry encryption appliance, which includes front-end compression. Differentiating it from other stand-alone encryption appliances, TapeSentry is based on Crossroads’ core router engine, providing full router functionality. The company claims wire-speed encryption. Other features of the TapeSentry encryption appliance include multi-streaming for LTO-3 tape drives, four 4Gbps Fibre Channel ports (which can be configured in any combination of host or device connections), AES-256 encryption algorithm, role-based user management, an audit log, support for access controls with user-defined encryption policies, key management and security, crypto-signed logging, pass-through for non-encrypted I/O, buffered tape writes and inquiry caching, and support for heterogeneous (multiple formats) tape environments. The appliances are priced at approximately $25,500. And, of course, users have the option of software-based encryption, which is available with many backup applications. The key advantage of hardware-based encryption versus software-based encryption is that it is faster and does not consume host resources. Related articles:
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