Tape Storage Automation: What it is and Why it's Important
TAPE STORAGE AUTOMATION: WHAT IT IS AND WHY IT'S IMPORTANT
With spiraling amounts of information being created, modified, and archived throughout business enterprises, automation of tape storage has become an essential tactical decision. Tape libraries featuring DLTtape system components provide a rugged, scalable, high-performance solution for information management.
Complex networks made up of servers, workstations, personal computers, and disk arrays tied into the astounding richness of data sources provide today's enterprises with new possibilities for success. In today's world, the network IS the computer. The enterprises that develop the best methods of using information, guaranteeing its integrity, and maximizing its availability have a tactical edge over their competition.
Information is a global resource and must be available 24 hours a day. I/S departments must preserve, protect, and make critical data available through regular, managed backup. Tape drives, tape drive technology, and storage management software applications have evolved over the decades as the cost-effective means for backup, near on-line, and archival storage. Automation provides the best solution for optimal storage management, combining consistent backup with the capacity and performance requirements that exceed a stand-alone drive solution.
INFORMATION MANAGEMENT CHALLENGES
The enterprise today has become an almost living organism with scarcely any down or dormant time. With activity taking place internationally, the luxury of lengthy time periods to perform backup of critical information no longer exists. I/S departments find less and less time available, and more and more information that must be protected. Stand-alone tape drives cannot support even mid-sized networks, and no I/S department has sufficient personnel to assign to the labor intensive task of swapping out tapes, even when each individual tape is of significant capacity.
Just how big is the data management challenge? It continues to expand with the explosive growth of client/server environments and the adoption of enterprise-wide applications such as SAP/R3, PeopleSoft, BAAN, Oracle, and CIS. With the proliferation of NT and Unix servers supporting these applications, the amount of data requiring management soars. Estimates are that by the year 2001, there will be 245,000 terabytes of information requiring storage on Unix systems, 350,000 terabytes on NT systems. In fact, the amount of data stored is growing by 50 to 100% per year. Only automated tape storage systems can provide cost-effective data storage services to support the volume of resulting mission-critical information.
STORAGE AUTOMATION OPTIONS - STACKERS, AUTOLOADERS, LIBRARIES
Tape storage automation is the combining of robotics with tape drives and complementary software resulting in a device that can load, unload, and swap tapes without operator intervention. The primary differences among tape automation systems are in the way they handle data backup and access management.
|"Typical" DLT Drive-Based Library Design shows DLT drives, robotic cartridge handling system, DLTtape cartridges, and controller mechanism|
Systems referred to as stackers are the first and simplest level of automated systems, providing support for small-scale I/S operations. Stackers typically are single drive configurations; tapes are inserted and removed in sequential order by the system's robotic picker. For a stacker to backup a database, the system would begin with tape 0 and continue inserting and removing tapes until the backup
was complete or the system ran out of available cartridges.
Autoloaders are automated systems that also have a single drive but have the ability to provide any of their tapes upon request. This random selection feature allows autoloader systems to support more sophisticated applications such as small-scale network backup and restore or near on-line storage.
Libraries offer functionality similar to autoloaders, but boast multiple tape drives and the ability to support larger scale backups, near on-line access, user-initiated file recovery and simultaneous support of multiple users and hosts. Libraries are more complex than stackers or autoloaders; typical library components include:
- The ability to accommodate two or more tape drives - The capabilities of the tape drive(s) selected as the heart of the library determine, typically, the performance, capacity, throughput, reliability, data compression, compatibility, and media consumption.
- Robotic loader mechanism - The robotic mechanism performs the movement of the tapes to and from the drive(s) within the library.
- Library and loader controllers - Libraries contain separate controllers to oversee overall library activity and robotic movement. These controllers carry the intelligence to perform the activities requested by the host.
- Bar code reader - The bar code reader enables the host software to track the location of files in and outside of the library. A bar code reader also accelerates the library file inventory process, eliminating the need to read the header of each tape in a library.
BENEFITS OF AUTOMATED STORAGE SYSTEMS
Automated tape systems provide room to keep up with the explosive growth of data. Their unmatched capacities and bandwidth coupled with the investment protection of scalability, make them the storage solution of choice.
Since the precision robotics of automated tape systems are responsible for loading and unloading tape cartridges, human intervention (the greatest single cause of data loss) is minimized. Human administration of the entire storage process is reduced, preventing errors caused by those types of activities. The result is less downtime in tape backup and data restoration: data protection occurs consistently and automatically.
As storage management costs fall, the cost effectiveness of automated tape storage systems increases and the return on investment accelerates. Guaranteed media rotation and storage management, improved data security and availability, and seamless disaster recovery are benefits of this class of storage system.
Multi-drive automation systems bring additional benefits. As the window of time to back up I/S systems shrinks, the increased bandwidth of multiple drives in an automated system allows data to be backed up much more quickly. Concurrent operations such as off-line copying and simultaneous backup and/or restoration can occur, and multi-host data transfer is supported, all with a significant level of redundancy and fault tolerance.
STORAGE AUTOMATION APPLICATIONS
As with stand-alone tape drives, the primary application for automated tape systems is backup/archiving. In addition to providing the only practical solution to managing the sheer volume of data across networks, automated systems maximize data integrity by removing the human element from the backup process. An incorrect tape cannot be loaded, a scheduled backup cycle cannot be forgotten. I/S personnel are free to perform other, more valuable tasks: automation reduces the administrative cost of mounting tape cartridges, estimated at over one dollar per cartridge.
Automated tape storage systems also play a key role in Hierarchical Storage Management (HSM). HSM is a storage strategy that places data on different types of storage media depending on how frequently the information is accessed: high-demand data is placed on fast disk, while data that is lower in demand can be stored on slower or cheaper media such as optical disk or tape. Managing data storage across media types is a complex application, but when implemented properly can reduce the total cost of storage and storage management. An effective HSM implementation can increase the total amount of storage that can be managed in a single installation, as well as presenting to the user the illusion of infinite disk space.
Other applications for tape automation systems include near-online storage, information archiving, data collection, remote vaulting (critical for disaster recovery), tape arrays, and image and video storage and distribution.
CASE-STUDY GLIMPSE: COST OF OWNERSHIP OF AUTOMATED TAPE STORAGE SYSTEM IMPRESSES PROFESSIONAL SERVICES FIRM
Faced with the challenge of implementing a backup solution for its distributed server network, a professional services firm reviewed a number of backup solutions and selected automated library systems built around the Quantum DLT 4000 tape drive. "We didn't want to buy a large juke box solution," said the project manager, "because it would be too expensive, given the number of servers we need to support." He saw this library as the most cost effective solution with the best combination of capacity, performance, and cost per gigabyte. He also felt the DLT-based solution was the easiest to use. "With a single DLTtape cartridge, we can back up as much as 40 gigabytes. That's a good match for our disk configurations."
This customer's business is supported by a network of seven Infrastructure Hub sites built around over 300 COMPAQ servers: hub servers, mail servers, and application servers. Hub servers support user accessible databases; mail servers store personal E-mail files; and application servers support individual applications. At each of the seven hub locations there are two hub servers and multiple E-mail servers. Each is supported by a tape storage library. In total, there are nearly a hundred of these libraries at the server.
All incremental data on the servers is backed up on the tape storage libraries on a daily basis. These backups mean that, even if there is a breakdown in the system and data or personal mail files are lost, the user is assured that he or she can go back to yesterday's backup and re-access personal E-mail files.
The project manager states that in this demanding backup environment, tape storage libraries with DLTtape system technology provide an effective solution, combining capacity, economy, and reliability. "The DLT libraries have greater capacity than DAT tape, they cost a lot less than big data-center-type juke boxes, and our experience indicates that we will have no reliability issues with the DLT libraries."
Through deployment of automated DLTtape storage systems, this customer increased the security of data and obtained labor cost savings, while establishing a reliable backup regimen for a sizable, complex installation.
As the amount of data needing management and storage continues to expand and the window of time available to perform backup of data shrinks, automated tape storage systems offer the cost-effective, reliable solution.