Tape Automation For The Rest Of Us.

Tape automation emerged first in the mainframe environment as a solution to the massive amount of tape handling required for batch systems. Large silos stored thousands of tape cartridges and these systems carried price tags of hundreds of thousands to millions of dollars. With the emergence of open systems, new tape library products appeared that moved the price point down to tens of thousands of dollars. These were used with high-end servers and large networks. Since the benefits of tape automation (elimination of human error, around the clock operation, and hands off operation) apply equally to low-end servers and smaller networks, there has been an unfulfilled need for a cost effective tape automation solution for the rest of us.

Although DDS has been the predominant tape backup technology for low-end servers, it has never successfully been implemented with tape automation. The DDS autoloader products, which were introduced, suffered from unreliable operation. Typical problems were associated with the DDS drives, which were not a high reliability technology. Some of the DDS autoloader products were designed in such a way that it was difficult to remove a jammed cartridge. Consequently, although there was a desire for tape automation in the low-end server market space, few automation products were purchased and installed.

There is now a more pressing need for tape automation in the low-end server environment. With the significant growth in disk capacity on even entry level servers and with the increasing amount of mission critical data being stored on these servers, it is imperative to have effective backup and restore solutions in this market space. The advantages of automation have become increasingly important to IT organizations that must support small servers and small networks.

Tape Automation For HAS And SAN

With the emergence of Network Attached Storage (NAS) and Storage Area Network (SAN) solutions, low cost tape automation will play an increasingly important role. The ability to cost effectively back up a NAS subsystem requires a tape automation subsystem that can either be integrated with the NAS subsystem itself or be directly network attached as another subsystem. SAN implementations are now moving from large organizations into medium-sized organizations that will require affordable tape automation solutions. This also requires the capability to connect an autoloader through a Fibre Channel bridge and, eventually, to have a native Fibre Channel controller in the autoloader itself.

Tape Automation Requirements

IT organizations seek autoloader solutions that can address the need for a full week's backup without having manual intervention. For decentralized servers, branch offices, and other distributed needs, it is important to be able to back up and restore data without human intervention. A one-drive autoloader meets the majority of needs in this environment. If the backup cycle is daily, then at least five cartridges of capacity are required. With many organizations doing daily incremental backup followed by a full backup over the weekend, at least six cartridges of capacity are important. Finally, if a cleaning cartridge is added or if the organization does backup seven days a week, seven-cartridge capacity in the autoloader becomes necessary.

There have been multiple technologies and products targeted at this need, but most were unable to meet the affordable tape automation requirement until now. With the breakthrough in price performance offered by the Benchmark DLT1 tape drive, it is now possible to place this drive in an autoloader that delivers over 500GB of storage capacity for a price lower than some high-end standalone tape drives such as the upcoming LTO products. This is possible since the DLT1 drive was designed from the ground up as a low-cost, reliable, automation-ready tape drive. In a seven-cartridge autoloader, this technology can support 280GB uncompressed and 5 60GB compressed capacity. This total tape automation solution is priced at under $5000.

In order to provide an affordable tape automation solution for the rest of us, it is important to maintain high reliability and single drive functionality and only include enough of the advanced features that don't increase the cost appreciably. An example of higher-end capabilities is bar coding, which is essential in large tape libraries, but not required for an entry-level autoloader. Cartridge swap time needs to be in the ten to 20 second range, but the expense of a faster and more intelligent loading mechanism can't be justified at this price point. Tape magazines, special entry ports, modular designs that hook together multiple products are nice features for higher end products, but go counter to the objective of low cost. An autoloader must provide at least seven cartridges of capacity to address the weekly backup cycle described above.

The DLTl tape drive was designed with automation as part of the market requirements that drove the development of the device. Some of the design strategies that were implemented in the DLT 1 design were soft-load cartridge mechanism, drive sled, low power consumption, library interface port, and LVD SCSI device interface.

The drive's soft-load mechanism removes the requirement for additional robotic mechanisms to operate the load handle that engages the cartridge clutch. By removing the additional robotic mechanism to operate a handle, not only have we removed cost but also added reliability to the unit. The original design of the DLT1 was a two-thirds high form factor device. In order to speed integration and increase drive reliability, we added a drive sled. This is a "Ushaped" piece of high strength sheet metal with shock mounts on each comer. This allows the throat height of the device to be at the identical location as current DLT products to speed up and ease the integration of the DLT1 into many of the autoloader products available today. The power consumption of the DLT1 averages 15 watts, which allows autoloader manufactures to use smaller power supplies, thereby reducing the cost and increasing reliability. The built-in library interface port manages all of the communications between the drive and the robotic mechan ism. This allows for the drive and library to pass both status information and commands between the two devices. No additional hardware is required to manage these communications.

The DLT1 tape drive is configured with a Low-Voltage-Differential (LVD) SCSI interface. By equipping the drive with this interface, it provides for coverage for most of the environments to which the drive or autoloader is targeted. The LVD interface is fully compatible with singleended buses and, therefore, end-users don't have to worry about selecting the correct interface to connect to their server. This simplifies the amount of configurations that need to be stocked in the distribution channel and lowers the cost of the unit to the end-user.

Therefore, by designing a tape drive like the DLT1 with automation as a requirement and by selecting automation partners that have been very successful in producing automation solutions targeted at the lower end of the server market, the combinations are multiple low cost autoloaders. IT managers looking for lowcost autoloaders will be able to choose from multiple vendors' product offerings that utilize the DLT1 tape drive as the enabling technology.

Finally, this architecture lends itself to the NAS and SAN solutions that are now being delivered. A low cost autoloader can be an important component to backup Network Attached Storage subsystems. Likewise, in a Storage Area Network, tape automation subsystems can be attached via a Fibre Channel bridge to a Fibre Channel hub or switch that, in tum, is connected to multiple servers and disk subsystems. These provide the elements to deliver cost effective LAN-less backup and server-less backup.

Tim Gerchar is the product marketing manager at Benchmark Tape Systems Corporation (Boulder CO).