What you will learn: This tip provides an overview of the Linear Tape-Open update to LTO-4, detailing its new features and what you need to consider before upgrading to LTO-4.

Backup tape technology is under pressure -- caught in the struggle between burgeoning enterprise storage demands and shrinking backup/restore windows. For older tape technologies, this has meant slow backups and a proliferation of cartridges that need to be tracked and managed. With the recent Linear Tape-Open (LTO) update to LTO-4, tape technology leaders, like IBM, HP, Quantum and Tandberg Data, hope to offer tape a bit of breathing room.

LTO-4 tape capacity and performance

As a removable media, pundits note that backup tape offers practically unlimited capacity -- you simply exchange tape cartridges. But tell that to any backup administrator and they'll point you to overcrowded tape autoloaders and lament the burden of managing hundreds, even thousands, of cartridges. The reality is that tapes still cost money, and they fill up quickly. LTO-4 tapes offer a native (uncompressed) capacity of 800 GB. This is double the capacity of LTO-3. LTO-4 tape drives, such as IBM's TS2430, tout native data transfer rates of 120 megabytes per second (MBps). When 2-to-1 compression is enabled, LTO-4 can achieve 1.6 terabytes (TB) of storage with effective data transfers of 240 MBps. The standard form factor for LTO cartridges is called Ultrium.

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LTO-4 tape encryption

Backup tape users are increasingly sensitive to data security in the wake of high profile data loss incidents, and encryption techniques have appeared to help ensure security. For example, if an unencrypted tape is lost or stolen, its data is at risk. But, if an encrypted tape is lost or stolen, its data is still considered to be secure. Thus, the use of encryption has a profound effect on corporate liability and reporting obligations.

Encryption has traditionally been performed through the backup software or through a standalone encryption appliance, but LTO-4 tape drives include 256-bit AES-GCM encryption as a native feature. Native encryption eliminates the performance penalty of software-based encryption and the expense of encryption appliances. However, encryption key management is a critical issue that a user should discuss with the LTO-4 vendor or value-added reseller (VAR).

LTO-4 backward compatibility

Since Ultrium drives are expected to read and write data to a cartridge in its own generation and at least the prior generation, LTO-4 tape drives should also be fully compatible with existing LTO-3 cartridges, though the capacity and performance benefits will be lost when using LTO-3 tapes. This will help to preserve any existing investment in LTO-3 media while LTO-4 drives and tapes are deployed.

This was first published in August 2007

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