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Buying your first backup tape library: What you need to know

What you will learn in this tip: Learn what you need to know when buying your first tape library for your small- to medium-sized business (SMB) data storage environment, including

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when to consider a tape library, the cost of libraries, which tape format best fits your storage needs, and the differences between tape libraries and autoloaders.

A tape library autoloader is a big step up from a tape drive when it comes to data backup. Backup tape autoloaders offer automatic tape swapping and generally higher reliability than a standalone tape drive. However, backup tape autoloaders have a limited capacity and throughput. If you have more than a few terabytes of storage, you should probably consider a backup tape library, the next step up.

Backup tape libraries have bigger capacities than tape drives, but they also have other advantages. "A tape library has more features [than an autoloader]," said Peri Grover, director of product marketing at Overland Storage Inc., a maker of both autoloaders and tape libraries. She said a tape library works when you have "more data and you need to get at it faster, manage it remotely or split it into virtual libraries."

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Generally speaking, a tape autoloader has a single tape drive and a robotic arm and can handle between four and 24 tapes. A tape library has two or more drives and robotic arms and can handle from 20 or so tapes up to thousands. According to Spectra Logic Corp., its T-Finity can handle up to 30,000 tapes.

Cost for a tape library typically starts at around $5,000. Hewlett Packard (HP) Co.'s MSL 6030 library starts at around $11,000 with two Linear Tape Open (LTO)-4 drives, 30 slots and a compressed capacity of 24 TB. Some tape libraries cost even less. The Quantum Corp. I40 has one drive (expandable to two), and is listed for less than $7,500. The Spectra Logic T24 has a starting price of just a little more than $5,000, but can run up to more than a million dollars for a very large unit. (The T-Finity will start at $218,000 for a "basic" configuration.)

Backup tape autoloaders vs. backup tape libraries

The difference between tape autoloaders and tape libraries is more than just the number of drives. Tape libraries are generally much more robustly built and reliable than autoloaders, and even the inexpensive ones, such at the Spectra Logic T24 come with built in bar code readers to help organize the tapes. Some libraries, such as the Qualstar Rackmount RLS-series, have components such as servo motors and precision lead screws in their robotic arms to more precisely and reliably position tapes.

High-end tape autoloaders slightly overlap in capacity and price with the least expensive libraries. The Quantum Corp. SuperLoader 3 can handle up to 24 TB of uncompressed data using LTO-5 tapes and compression. The list price for the Quantum SuperLoader 3 is $5000.

Make sure you shop around when looking for a tape library because many libraries can take several different kinds of drives. For example, the Qualstar Rackmount RLS-series can take either LTO-4 or AIT drives.

Most tape libraries, even the inexpensive ones, now offer encryption. For example, the Quantum I40 comes with a tape encryption standard. Encryption is especially important when you have to take tapes off site because it protects you in the event of a lost or stolen tape.

In addition to encryption, many libraries, such as HP's ESL E-seriesoffer write once, read many (WORM) capability for increased data security and compliance.

Earlier generations of tape drives are popular in bottom end tape libraries because of their lower cost. For example, the Spectra Logic Spectra T24 has a starting price of around $5,000 with an LTO-3 drive. But be careful with these. Although an older generation ape library is cheaper, consider first how much you expect your data storage news to grow. The older drives have less capacity than the newer ones, so after a few years, you may find yourself buying additional older drives for your storage needs. For example, the T24 with LTO-3 drive maxes out at 9.6 TB uncompressed.

In tape libraries today, LTO-4 is currently the most popular format. However, LTO-5 is just beginning to arrive and will become increasingly popular as more manufacturers start to offer it. Some companies, like Spectra Logic, are offering their low-end tape libraries, such as the T-50 with replacement agreements where they will replace the LTO-4 drives on libraries purchased now with LTO-5 drives as they become available.

The market for low-end tape libraries is highly competitive, so it pays to shop around.

What to look for when shopping for a backup tape library

When shopping for a backup tape library, it's important to anticipate your growth in data storage requirements. Fortunately, all but the most bare-bones libraries can be expanded by adding more tape slots and additional drives and robots. Many tape libraries can be expanded simply by adding cartridge slots, or in some cases, like the HP ESL E-series, by having the vendor throw a software switch. For greater expandability you can add additional drives and robots in modules with more slots.

In addition to cost, the other main disadvantage to a tape library is complexity. "It's a significantly more complex environment," Grover said. Unlike autoloaders, libraries have to be managed by the system's backup software, and the ability to do things like split a library into multiple virtual libraries require more sophisticated management.

About this author: Rick Cook specializes in writing about issues related to storage and storage management.


This was first published in June 2010

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